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Effectively harnessing solar energy for the conversion of CO 2 into valuable chemical energy presents a viable solution to address energy scarcity and climate change concerns. Nonetheless, the limited light absorption and sluggish charge kinetics significantly hinder the photoreduction of CO 2 . In this study, we employed a facile sol-gel method combined with wetness impregnation to synthesize Cu-doped TiO 2 coated with NiO x nanoparticles. Various characterizations verified the successful incorporation of Cu ions into the TiO 2 crystal lattice and the formation of NiO x co-catalysts within the composites. The optimal performance attained with CTN-0.5 demonstrates an output of 11.85 μmol h -1 g -1 for CO and 9.51 μmol h -1 g -1 for CH 4 , which represent a 4.4-fold and 15.6-fold increase, respectively, compared to those achieved with pure TiO 2 . The induced Cu defect band broadens the light absorption by decreasing the conduction band edge of TiO 2 , while NiO x upshifts the valence band of TiO 2 because of the interaction of valence orbitals. Light irradiation EPR and FTIR tests suggest that the collaboration of CuO x and NiO x promotes the formation of oxygen vacancies/defects and a rapid charge transfer pathway, thereby provides numerous active sites and electrons to enhance CO 2 photoreduction performance.

MOF-based photoelectrocatalysis (PEC) using CO 2 as an electron donor offers a green, clean, and extensible way to make hydrocarbon fuels under more tolerant conditions. Herein, basic principles of PEC reduction of CO 2 and the preparation methods and characterization techniques of MOF-based materials are summarized. Furthermore, three applications of MOFs for improving the photoelectrocatalytic performance of CO 2 reduction are described: (i) as photoelectrode alone; (ii) as a co-catalyst of semiconductor photoelectrode or as a substrate for loading dyes, quantum dots, and other co-catalysts; (iii) as one of the components of heterojunction structure. Challenges and future wave surrounding the development of robust PEC CO 2 systems based on MOF materials are also discussed briefly.

Transforming CO 2 into renewable fuels or valuable carbon compounds could be a practical means to tackle the issues of global warming and energy crisis. Photocatalytic CO 2 reduction is more energy-efficient and environmentally friendly, and offers a broader range of potential applications than other CO 2 conversion techniques. Ferroelectric materials, which belong to a class of materials with switchable polarization, are attractive candidates as catalysts due to their distinctive and substantial impact on surface physical and chemical characteristics. This review provides a concise overview of the fundamental principles underlying photocatalysis and the mechanism involved in CO 2 reduction. Additionally, the composition and properties of ferroelectric materials are introduced. This review expands on the research progress in using ferroelectric materials for photocatalytic reduction of CO 2 from three perspectives: directly as a catalyst, by modification, and construction of heterojunctions. Finally, the future potential of ferroelectric materials for photocatalytic CO 2 reduction is presented. This review may be a valuable guide for creating reasonable and more effective photocatalysts based on ferroelectric materials.

Solar-energy-driven CO 2 hydrogenation is a promising strategy to alleviate the climate crisis. Methane is a desirable derivative of CO 2 reduction. However, developing a photocatalyst for highly active and selective CH 4 generation remains challenging. Herein, we report a double Z-scheme Bi 3 O 4 Cl/g-C 3 N 4 /Cd 0.5 Zn 0.5 S photocatalyst for efficient reduction of CO 2 to CH 4 . In situ characterization techniques confirmed that the charge migration mechanism in Bi 3 O 4 Cl/g-C 3 N 4 /Cd 0.5 Zn 0.5 S promotes charge separation through double internal electric fields. As a result, the optimized C0.01B0.02C catalyst displayed a formation rate high up to 25.34 μmol g -1 h -1 and a selectivity of 96.52% of CH 4 . Moreover, the AQY of CO 2 conversion on C0.01B0.02C (1.84%) was almost 41 times higher than that of the bare CN. This study provides a novel perspective to develop heterojunction photocatalysts for selective CO 2 conversion to CH 4 .

Carbon capture, utilization, and storage (CCUS) technology is widely recognized as a key solution for mitigating global climate change. Consequently, it has received significant attention from countries worldwide. However, carbon dioxide corrosion poses a significant challenge to CCUS and represents a bottleneck to the large-scale development and application of this technology. To mitigate this issue, this review starts with a discussion of corrosion problems in CCUS. Later, the fundamentals of the carbon dioxide corrosion mechanism are introduced. Then, the influences of various factors that affect the corrosion are highlighted, such as water content, pH, flow rate, etc. Afterward, we summarize the commonly used methods for corrosion protection, with a particular focus on inhibitor, given their eco-friendly and effective nature. Lastly, challenges and prospects are discussed to motivate future studies on developing novel, high-performance green inhibitor and studying the corresponding protection mechanisms, hoping to make some contributions to carbon emission reduction., Competing Interests: The authors declare no competing interests., (© 2023 The Authors.)

Converting CO 2 into chemicals and fuels by solar energy can alleviate global warming and solve the energy crisis. In this work, CoAl-LDO/MoO 3-x (LDO/MO) composites were successfully prepared and achieved efficient CO 2 reduction under visible light. The CoAl-layered double oxides (CoAl-LDO) evolved from CoAl-layered double hydroxide (CoAl-LDH) exhibited a more robust structure, broader light absorption, and improved CO 2 adsorption ability. The local surface plasmon resonance (LSPR) effect excited by nonstoichiometric MoO 3-x broadened the photo-response range of CoAl-LDO/MoO 3-x . In addition, constructing step-scheme (S-scheme) heterojunctions could simultaneously optimize the migration mechanism of photogenerated electrons and holes, and retain carriers with strong redox ability. Therefore, the production rates of CO and CH 4 on the optimal LDO/MO composite were 7 and 9 times higher than the pristine CoAl-LDH, respectively. This work hybridizes oxidation photocatalysts and LDO-based materials to optimize the charge separation and migration mechanisms, which guides the modification of LDO-based materials., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Covalent organic frameworks (COFs) are one type of porous organic materials linked by covalent bonds. COFs materials exhibit many outstanding characteristics such as high porosity, high chemical and thermal stability, large specific surface area, efficient electron transfer efficiency, and the ability for predesigned structures. These exceptional advantages enable COFs materials to exhibit remarkable performance in photocatalysis. Additionally, the activity of COFs materials as photocatalysts can be significantly upgraded by ion doping and the formation of heterojunctions. This paper summarizes the latest research progress on COF-based materials applied in photocatalytic systems. Initially, typical structures and preparation methods of COFs are analyzed and compared. Moreover, the essential principles of photocatalytic reactions over COFs-based materials and the latest research developments in photocatalytic hydrogen production, CO 2 reduction, pollutants elimination, organic transformation, and overall water splitting are indicated. At last, the outlook and challenges of COF-based materials in photocatalysis are discussed. This review is intended to permit instructive guidance for the efficient use of photocatalysis based on COFs in the future., (© 2023 Wiley-VCH GmbH.)

In this research, a ternary Cu-CuTCPP/Cu 2 O/CoAl-LDH composite with a dual Z-scheme heterostructure was fabricated based on a Cu 2 O photocatalyst and applied in photocatalytic CO 2 reduction. The physicochemical properties of the prepared catalysts and the possible reaction mechanism in CO 2 reduction were analyzed and studied by various characterization methods. The activity of CO 2 reduction significantly increased, especially forming C2 products. The optimal yield of C 2 H 4 and C 2 H 6 reached 1.56 and 1.92 μmol g -1 h -1 respectively, which was 14.45 and 17.45 times that from using the Cu 2 O monomer. In addition, the selectivity of C2 products reached 37.4%. The satisfactory C2 yield was mainly due to the fact that Cu 1+ δ 2 (COO) 3 nodes in Cu-CuTCPP contained adjacent Cu sites, which effectively promoted the C-C coupling reaction. Moreover, the dual Z-scheme heterojunction stimulated the separation of photogenerated electron-hole pairs and diminished the recombination rate. This work contributes to the development of novel photocatalysts with a dual Z-scheme heterojunction and facilitates the generation of valuable C2 products.

Photocatalytic CO 2 reduction to valuable fuels is a promising way to alleviate anthropogenic CO 2 emissions and energy crises. Perovskite oxides have attracted widespread attention as photocatalysts for CO 2 reduction by virtue of their high catalytic activity, compositional flexibility, bandgap adjustability, and good stability. In this review, the basic theory of photocatalysis and the mechanism of CO 2 reduction over perovskite oxide are first introduced. Then, perovskite oxides' structures, properties, and preparations are presented. In detail, the research progress on perovskite oxides for photocatalytic CO 2 reduction is discussed from five aspects: as a photocatalyst in its own right, metal cation doping at A and B sites of perovskite oxides, anion doping at O sites of perovskite oxides and oxygen vacancies, loading cocatalyst on perovskite oxides, and constructing heterojunction with other semiconductors. Finally, the development prospects of perovskite oxides for photocatalytic CO 2 reduction are put forward. This article should serve as a useful guide for creating perovskite oxide-based photocatalysts that are more effective and reasonable., (© 2023 Wiley-VCH GmbH.)

Energy shortage and global warming caused by the extensive use of fossil fuels are urgent problems to be solved at present. Photoreduction of CO 2 is considered to be a feasible solution. The ternary composite catalyst g-C 3 N 4 /Ti 3 C 2 /MoSe 2 was synthesized by hydrothermal method, and its physical and chemical properties were studied by an array of characterization and tests. In addition, the photocatalytic performance of this series of catalysts under full spectrum irradiation was also tested. It is found that the CTM-5 sample has the best photocatalytic activity, and the yields of CO and CH 4 are 29.87 and 17.94 μmol g -1  h -1 , respectively. This can be ascribed to the favorable optical absorption performance of the composite catalyst in the full spectrum and the establishment of S-scheme charge transfer channel. The formation of heterojunctions can effectively promote charge transfer. The addition of Ti 3 C 2 materials provides plentiful active sites for CO 2 reaction, and its superior electrical conductivity is also favorable for the migration of photogenerated electrons., (© 2023 Wiley-VCH Verlag GmbH.)

Ammonia selective catalytic reduction (NH 3 -SCR) of nitrogen oxides is an effective and well-established technology for NO x removal, but current commercial denitrification catalysts based on V 2 O 5 -WO 3 /TiO 2 have some obvious disadvantages, including narrow operating temperature windows, toxicity, poor hydrothermal stability, and unsatisfied SO 2 /H 2 O tolerance. To overcome these drawbacks, it is imperative to investigate new types of highly efficient catalysts. In order to design catalysts with outstanding selectivity, activity, and anti-poisoning ability, core-shell structured materials have been widely applied in the NH 3 -SCR reaction, which exhibits numerous advantages including the large surface area, the strong synergy interaction of core-shell materials, the confinement effect, and the shielding effect from the shell layer to protect the core. This review summarizes recent developments of core-shell structured catalysts for NH 3 -SCR, including basic classification, synthesis methods, and a detailed description of the performance and mechanisms of each type of catalyst. It is hoped that the review will stimulate future developments in NH 3 -SCR technology, leading to novel catalyst designs with improved denitrification performance., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

In this study, an expanded graphite (EG) with nano-CuS (EG/CuS) support material with a special morphology was prepared, with EG/CuS filled with different ratios of palmitic acid (PA). Finally, a PA/EG/CuS composite phase change thermal storage material with photothermal conversion performance was synthesized. The superb chemical and thermal stability of PA/EG/CuS was demonstrated by characterization and analysis of the experiments. EG, a multi-layer structured material, provides rich binding sites for PA and nano-CuS and constructs rich thermal conductivity paths, which effectively improves the thermal conductivity of PA/EG/CuS. It is noted that the maximum thermal conductivity of PA/EG/CuS reached 0.372 W m -1 K -1 and the maximum phase change thermal storage capacity reached 260.4 kJ kg -1 , which proved the excellent thermal storage properties of PA/EG/CuS. In addition, PA/EG/CuS exhibits excellent photothermal conversion performance, and the experimental results demonstrated that the best photothermal conversion efficiency of PA/EG/CuS reached 81.4%. The PA/EG/CuS developed in this study provides a promising method for fabricating excellent conductive and low leakage composite phase change materials for solar energy utilization and energy storage.

Photocatalysis driven by solar energy is a feasible strategy to alleviate energy crises and environmental problems. In recent years, significant progress has been made in developing advanced photocatalysts for efficient solar-to-chemical energy conversion. Single-atom catalysts have the advantages of highly dispersed active sites, maximum atomic utilization, unique coordination environment, and electronic structure, which have become a research hotspot in heterogeneous photocatalysis. This paper introduces the potential supports, preparation, and characterization methods of single-atom photocatalysts in detail. Subsequently, the fascinating effects of single-atom photocatalysts on three critical steps of photocatalysis (the absorption of incident light to produce electron-hole pairs, carrier separation and migration, and interface reactions) are analyzed. At the same time, the applications of single-atom photocatalysts in energy conversion and environmental protection (CO 2 reduction, water splitting, N 2 fixation, organic macromolecule reforming, air pollutant removal, and water pollutant degradation) are systematically summarized. Finally, the opportunities and challenges of single-atom catalysts in heterogeneous photocatalysis are discussed. It is hoped that this work can provide insights into the design, synthesis, and application of single-atom photocatalysts and promote the development of high-performance photocatalytic systems., (© 2023 Wiley-VCH GmbH.)

A photocatalytic system driven by solar light is one of the promising strategies for converting CO 2 into valuable energy. The reduction of CO 2 to CH 4 is widely studied since CH 4 has a high energy density as the main component of nonrenewable natural gas. Therefore, it is necessary to develop semiconductor materials with high photocatalytic activity and CH 4 selectivity. Graphitic carbon nitride (g-C 3 N 4 /CN) has attracted widespread attention for photocatalytic CO 2 reduction due to its excellent redox ability and visible light response. A hybrid system constructed by loading cocatalysts on g-C 3 N 4 can significantly improve the yield of target products, and serve as a general platform to explore the mechanism of the CO 2 reduction reaction. Herein, we briefly introduce the theory of selective CO 2 photoreduction and the basic properties of cocatalysts. Then, several typical configurations and modification strategies of cocatalyst/CN systems for promoting CH 4 selective production are presented in detail. In particular, we systematically summarize the application of cocatalyst/CN composite photocatalysts in the selective reduction of CO 2 to methane, according to the classification of cocatalysts (monometal, bimetal, metal-based compound, and nanocarbon materials). Finally, the challenges and perspectives for developing cocatalyst/g-C 3 N 4 systems with high CH 4 selectivity are presented to guide the rational design of catalysts with high performance in the future.

The photocatalytic reduction of CO 2 to hydrocarbons is expected to simultaneously alleviate the energy crisis and greenhouse effect. Herein, the ternary BiOCl/C/Cu 2 O catalysts with different mass ratios were compounded using a simple hydrothermal method, revealing better photocatalytic activity than the monomer. In the absence of sacrificial agents and photosensitizers, 25% BiOCl/C/Cu 2 O showed optimal photocatalytic performance. The CO and CH 4 yields over 25% BiOCl/C/Cu 2 O reached 26.77 and 9.86 μmol g -1 h -1 , which is 2.9 and 8.7 times higher than that of the pristine Cu 2 O, respectively. The ameliorative activity can be attributed to the construction of the Z-scheme heterostructure and carbon layer, which are conducive to the transfer and separation of photogenerated carriers. This study offers valuable references for the design and investigation of a Z-scheme heterojunction using a carbon layer as an electron transfer medium.

Converting CO 2 into value-added products by photocatalysis, electrocatalysis, and photoelectrocatalysis is a promising method to alleviate the global environmental problems and energy crisis. Among the semiconductor materials applied in CO 2 catalytic reduction, Cu 2 O has the advantages of abundant reserves, low price and environmental friendliness. Moreover, Cu 2 O has unique adsorption and activation properties for CO 2 , which is conducive to the generation of C 2+ products through CC coupling. This review introduces the basic principles of CO 2 reduction and summarizes the pathways for the generation of C 1 , C 2 , and C 2+ products. The factors affecting CO 2 reduction performance are further discussed from the perspective of the reaction environment, medium, and novel reactor design. Then, the properties of Cu 2 O-based catalysts in CO 2 reduction are summarized and several optimization strategies to enhance their stability and redox capacity are discussed. Subsequently, the application of Cu 2 O-based catalysts in photocatalytic, electrocatalytic, and photoelectrocatalytic CO 2 reduction is described. Finally, the opportunities, challenges and several research directions of Cu 2 O-based catalysts in the field of CO 2 catalytic reduction are presented, which is guidance for its wide application in the energy and environmental fields is provided., (© 2023 Wiley-VCH GmbH.)

In recent years, three-dimensionally ordered macroporous (3DOM) materials have attracted tremendous interest in the field of photocatalysis due to the periodic spatial structure and unique physicochemical properties of 3DOM catalysts. In this review, the fundamentals and principles of 3DOM photocatalysts are briefly introduced, including the overview of 3DOM materials, the photocatalytic principles based on 3DOM materials, and the advantages of 3DOM materials in photocatalysis. The preparation methods of 3DOM materials are also presented. The structure and properties of 3DOM materials and their effects on photocatalytic performance are briefly summarized. More importantly, 3DOM materials, as a supported catalyst, are extensively employed to combine with various common materials, including metal nanoparticles, metal oxides, metal sulfides, and carbon materials, to enhance photocatalytic performance. Finally, the prospects and challenges for the development of 3DOM materials in the field of photocatalysis are presented., (© 2023 Wiley-VCH GmbH.)

Photocatalytic CO 2 conversion into solar fuels is a promising technology to alleviate CO 2 emissions and energy crises. The development of core-shell structured photocatalysts brings many benefits to the photocatalytic CO 2 reduction process, such as high conversion efficiency, sufficient product selectivity, and endurable catalyst stability. Core-shell nanostructured materials with excellent physicochemical features take an irreplaceable position in the field of photocatalytic CO 2 reduction. In this review, the recent development of core-shell materials applied for photocatalytic reduction of CO 2 is introduced . First, the basic principle of photocatalytic CO 2 reduction is introduced. In detail, the classification and synthesis techniques of core-shell catalysts are discussed. Furthermore, it is also emphasized that the excellent properties of the core-shell structure can greatly improve the activity, selectivity, and stability in the process of photocatalytic CO 2 reduction. Hopefully, this paper can provide a favorable reference for the preparation of efficient photocatalysts for CO 2 reduction., (© 2022 Wiley-VCH GmbH.)

Photocatalytic reduction of CO 2 to high-energy products is an effective way to utilize solar energy and mitigate the greenhouse effect. In this paper, a series of CQDs/Bi 12 O 17 Cl 2 /NiAl-LDH (C/BOC/LDH) photocatalysts were prepared via a one-pot hydrothermal method, demonstrated excellent photocatalytic CO 2 reduction performance. In the case of only water without any photosensitizer and sacrificial agent, the CO production rate on C/0.3BOC/LDH reached 16.4 μmol·g -1 h -1 , which is 6.7 times higher than that of the original LDH. The construction of Z-scheme heterojunctions inhibited the recombination of electrons with holes. The unique up-conversion PL behavior of CQDs benefitted the absorption of energy in the NIR by the photocatalyst. This study provides meaningful assistance for the design and construction of a ternary photocatalytic system with Z-scheme heterojunction and carbon-based co-catalyst., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Reducing CO 2 into value-added chemicals and fuels by artificial photosynthesis (photocatalysis and photoelectrocatalysis) is one of the considerable solutions to global environmental and energy issues. One-dimensional (1D) nanostructured catalysts (nanowires, nanorods, nanotubes and so on.) have attracted extensive attention due to their superior light-harvesting ability, co-catalyst loading capacity, and high carrier separation rate. This review analyzed the basic principle of the photo(electro)catalytic CO 2 reduction reaction (CO 2 RR) briefly. The preparation methods and properties of 1D nanostructured catalysts are introduced. Next, the applications of 1D nanostructured catalysts in the field of photo(electro)catalytic CO 2 RR are introduced in detail. In particular, we introduced the design of composite catalysts with 1D nanostructures, for example loading 0D, 1D, 2D, and 3D materials on a 1D nanostructured semiconductor to construct a heterojunction to optimize the photo-response range, carrier separation and transport efficiency, CO 2 adsorption and activation capacity, and stability of the catalyst. Finally, the development prospects of 1D nanostructured catalysts are discussed and summarized. This review can provide guidance for the rational design of advanced catalysts for photo(electro)catalytic CO 2 RR.

Photocatalytic CO 2 reduction technology has a broad potential for dealing with the issues of energy shortage and global warming. As a widely studied material used in the photocatalytic process, titanium dioxide (TiO 2 ) has been continuously modified and tailored for more desirable application. Recently, the defective/reduced titanium dioxide (TiO 2- x ) catalyst has attracted broad attention due to its excellent photocatalytic performance for CO 2 reduction. In this perspective review, we comprehensively present the recent progress in TiO 2- x -based materials for photocatalytic CO 2 reduction. In detail, the review starts with the fundamentals of CO 2 photocatalytic reduction. Then, the synthesis of a defective TiO 2 structure is introduced for the regulation of its photocatalytic performance, especially its optical properties and dissociative adsorption properties. In addition, the current application of TiO 2- x -based photocatalysts for CO 2 reduction is also highlighted, such as metal-TiO 2- x , oxide-TiO 2- x and TiO 2- x -carbon-based photocatalysts. Finally, the existing challenges and possible scope of photocatalytic CO 2 reduction over TiO 2- x -based materials are discussed. We hope that this review can provide an effective reference for the development of more efficient and reasonable photocatalysts based on TiO 2- x .

As a renewable green energy, hydrogen has received widespread attention due to its huge potential in solving energy shortages and environment pollution. In this paper, a one-step solvothermal method was applied to grow ultra-thin g-C 3 N 4 (UCN) nanosheets and NiS nanoparticles on the surface of ZnIn 2 S 4 (ZIS). A ternary NiS/ZnIn 2 S 4 /ultra-thin-g-C 3 N 4 composite material with dual high-speed charge transfer channels was constructed for the advancement of the photocatalytic H 2 generation. The optimal ternary catalyst 1.5wt.%NiS/ZnIn 2 S 4 /ultra-thin-g-C 3 N 4 (NiS/ZIS/UCN) achieved a H 2 evolution yield reached to 5.02 mmolg -1 h -1 , which was 5.23 times superior than that of pristine ZnIn 2 S 4 (0.96 mmolg -1 h -1 ) and even outperform than that of the best precious metal modified 3.0 wt%Pt/ZnIn 2 S 4 (4.08 mmolg -1 h -1 ). The AQY at 420 nm could be achieved as high as 30.5%. The increased photocatalytic performance of NiS/ZIS/UCN could be ascribed to the type-I heterojunctions between intimated ZIS and UCN. In addition, NiS co-catalyst with large quantity of H 2 evolution sites, could result in efficient photo-induced charges separation and migration. Furthermore, the NiS/ZIS/UCN composite exhibited excellent H 2 evolution stability and recyclability. This work would also offer a reference for the design and synthesis of ternary co-catalyst with heterojunction composite for green energy conversion., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Pyrolysis polygeneration technology has been widely applied due to its wide adaptability to coal types and mild reaction conditions. In this paper, the in situ process test combining pyrolysis and combustion of Pingshuo coal was carried out using a thermogravimetric analyzer and a fluidized-bed reactor. The influence of pyrolysis conditions on the combustion behavior and char structure was studied. The reduction of the pyrolysis temperature and the increase in pyrolysis residence time resulted in a lower burnout temperature of char, thereby improving the combustion characteristics of char. Furthermore, the maximum CO 2 release rate reached 2.8 mg/(g·s) during the combustion process. The decrease in the pyrolysis temperature was conducive to the increase of CO 2 release mass, suggesting a more complete burning of char. The char combustion process was mainly controlled by the chemical reaction according to the reaction kinetics study. The apparent rate constant of the combustion process increased gradually with the decrease in the pyrolysis temperature of char, and the rate of the combustion reaction increased, which contributed to the enhancement of the combustion performance of the char within the range of 850-950 °C. Meanwhile, the crystal structure inside the char changed significantly after different pyrolysis conditions. However, it had little influence on the molar content of carbon structure, which suggested that the amount of CO 2 released was mainly caused by the different resistances of oxygen diffusion to the reaction interface., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Photocatalytic degradation technology is regarded as a promising technology for dye-contained wastewater treatment due to its superior efficiency and recycling. The key to the implementation of photocatalytic degradation technology is the selection of sunlight-active photocatalyst. Graphitic carbon nitride (g-C 3 N 4 ) photocatalyst has been put into a lot of research in the field of organic pollutant degradation because of its low cost, suitable electronic structure and high chemical stability. In this perspective review, we comprehensively discuss the recent advance of photocatalytic dyes degradation over g-C 3 N 4 -based materials. The properties, structure and preparation methods of g-C 3 N 4 are briefly introduced. Furthermore, the progress in improving the degradation efficiency of g-C 3 N 4 -based photocatalyst is highlighted in the article. The possible pathways and different active species for dyes decomposition are also summarized. We expect this review can provide instructive application of g-C 3 N 4 -based catalysts for environmental remediation., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Selective catalytic reduction with NH 3 (NH 3 -SCR) was the most efficient approach to mitigate the emission of nitrogen oxides (NO x ). Although the conventional manganese oxide-based catalyst had gradually become a kind of principal catalyst for the low-temperature NH 3 -SCR reaction, there were still numerous defects. The growing demands for extensive operation temperature scope, strong SO 2 tolerance, and excellent catalytic activity had boosted the development of novel manganese oxide-based catalysts. In this review, three forms of manganese oxide-based catalysts were introduced in detail, including single manganese oxide catalysts, composite manganese oxide-based catalysts, and supported manganese oxide-based catalysts. The surface acidity and redox properties of manganese oxide-based catalysts could be strengthened by optimizing the preparation methods, exposing specific crystal planes, and constructing multiple active centers and sacrificial sites, which improved the SCR performance and anti-poisoning properties of catalysts. Secondly, we briefly summarized the NH 3 -SCR reaction mechanism of manganese oxide-based catalysts, including the Eley-Rideal (E-R) mechanism and the Langmuir-Hinshelwood (L-H) mechanism. Finally, several overtures were proposed for the future research directions of manganese oxide-based catalysts for NH 3 -SCR reaction, hoping to narrow the gap between the novel manganese oxide-based catalysts and the actual demands and realize commercialized application in the nearest future.

Converting CO 2 to renewable fuels or valuable carbon compounds is an effective way to solve the global warming and energy crisis. Compared with other CO 2 conversion methods, photocatalytic reduction of CO 2 is more energy-saving, environmentally friendly, and has a broader application prospect. Layered double hydroxide (LDH) has attracted widespread attention as a two-dimensional material, composed of metal hydroxide layers, interlayer anions and water molecules. This review briefly introduces the basic theory of photocatalysis and the mechanism of CO 2 reduction. The composition and properties of LDH are introduced. The research progress on LDH in the field of photocatalytic reduction of CO 2 is elaborated from six aspects: directly as a catalyst, as a precursor for a catalyst, and by modification, intercalation, supporting with other materials and construction of a heterojunction. Finally, the development prospects of LDH are put forward. This review could provide an effective reference for the development of more efficient and reasonable photocatalysts based on LDH.

S-scheme heterostructure can facilitate the separation of carriers while maintain outstanding redox capacity. A series of ternary Bi 7 O 9 I 3 /g-C 3 N 4 /Bi 3 O 4 Cl photocatalytic system was triumphantly synthesized via oil bath method in this work and used in photocatalytic degradation of phenol. The optimal TOC removal rate reached up to 93.57% under illumination for 160 min, which was slightly lower than phenol photodegradation (about 100%, 100 min). Correspondingly, the apparent rate constants for the decay of phenol are determined to be 0.0211 min -1 . The experiment of free radical capture indicated that ·OH and ·O 2 - were the major oxidizing substances to degrade phenol. The products of phenol photodegradation were identified by high performance liquid chromatography (HPLC) and a possible degradation pathway was proposed. The characterization analysis and density functional theory (DFT) calculations demonstrated that dual S-scheme charge migration was generated at the interface of Bi 7 O 9 I 3 , g-C 3 N 4 and Bi 3 O 4 Cl, contributing to an efficient separation of light-excited carriers. In the field of environmental remediation, the discovery of this work could open up promising vistas for designing bismuth-based ternary heterostructures with application potentiality., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Promoting the separation of photogenerated electron-hole pairs and enhancing the charge carrier transfer are critical in photocatalysis. In our work, a ball-flower-like NiS/Zn 3 In 2 S 6 /g-C 3 N 4 photocatalyst fabricated by a hydrothermal method exhibited superior performance for photocatalytic water splitting. The optimized 2.0% NiS/Zn 3 In 2 S 6 /g-C 3 N 4 rivaled noble metal based Pt/g-C 3 N 4 and showed an apparent quantum efficiency (AQE) of 24.3% at 420 nm, with a H 2 yield of 4.135 mmol g -1 h -1 , which was 30.4 and 9.51 times that of pure g-C 3 N 4 and binary Zn 3 In 2 S 6 /g-C 3 N 4 composites, respectively. The experimental and characterization results suggested that the heterojunction formed between Zn 3 In 2 S 6 /g-C 3 N 4 and the decorating NiS co-catalyst cooperatively suppressed the electron-hole recombination and facilitated the charge carrier transfer, thus resulting in significant improvement of the H 2 evolution performance. Moreover, the increased specific surface area and the enhanced visible-light absorption also contributed to superior water splitting performance. The prepared ternary catalytic system with the heterojunction and non-noble metal co-catalyst has great potential as an alternative to noble metals for achieving cost-efficient water splitting systems.

The waste tire is a fuel with the potential to partially replace coal due to the high heat value. In the present study, the combustion characteristics of the tire powders, bituminous coal, and their blends were examined using the thermogravimetric analyzer. The influence of heating rate on tire powders combustion and the burnout characteristics of their blends were studied. The increase of the heating rate caused the combustion temperature of the tire powders to become high but reduced the maximum weight loss rate. The combustion characteristics of the blends of coal and tire powders approached the combination of those of the individual sample, suggesting that the interaction effects between coal and tire powders were slight. Furthermore, the influence of different ratios on ignition characteristics, burnout temperature, and combustion effect of the blends was studied at the optimal combustion rate. The addition of tire powders improved the ignition characteristics, reduced the burnout temperature and increased the burnout rate of coal to a certain extent. An increase in the proportion of tire powders led to a decrease in the activation energy in the temperature range of 349-465 °C, whereas it caused an increase from 465 °C to burnout, which could be attributed to the fact that the volatile matter was more combustible than fixed carbon within 349-465 °C, and the combustion effect of fixed carbon in the tire powders gradually manifested in the combustion from 465 °C to burnout when the tire powders content increased., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Photocatalytic hydrogen evolution can effectively alleviate the troublesome global energy crisis by converting solar energy into the chemical energy of hydrogen. In order to realize efficient hydrogen generation, a variety of semiconductor materials have been extensively investigated, including TiO 2 , CdS, g-C 3 N 4 , metal-organic frameworks (MOFs), and others. In recent years, to achieve higher photocatalytic performance and reach the level of large-scale industrial applications, photocatalysts decorated with transition metal phosphides (TMPs) have shone brightly because of their low cost, stable physical and chemical properties, and substitution for precious metals of TMPs. This Review highlights the preparation methods and properties associated with photocatalysis of TMPs. Moreover, the H 2 generation efficiency of photocatalysts loaded with TMPs and the roles of TMPs in catalytic systems are also studied systematically. Apart from being co-catalysts, several TMPs can also serve as host catalysts to boost the activity of photocatalytic composites. Finally, the development prospects and challenges of TMPs are put forward, which is valuable for future researchers to expand the application of TMPs in photocatalytic directions and to develop more active photocatalytic systems., (© 2020 Wiley-VCH GmbH.)

Catalytic oxidation is a promising technique to control the emission of gaseous pollutants. Three-dimensionally ordered macroporous (3DOM)-based catalysts have aroused widespread attention because of their high porosity, large surface area and pore volume, superb ability of mass transfer. Therefore, they have been widely used in gaseous pollutants control field, such as soot and methane catalytic combustion, VOCs catalytic oxidation, photocatalytic CO 2 reduction and so on. In this review, the recent studies about the preparation and applications of 3DOM catalysts are summarized. At the same time, the advantages and mechanism of the 3DOM catalysts used in gaseous pollutants control are introduced in depth. Finally, the perspective and future direction of 3DOM-based catalysts for gaseous pollutants control are proposed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In this study, it was found that the CeVO 4 -CeO 2 nanocomposite possessed remarkably selective catalytic reduction (SCR) performance and wider active temperature scope. And, the promotion principle was explored based on BET, XRD, XPS, H 2 -temperature-programmed reduction, NH 3 -temperature-programmed desorption, and in situ diffuse reflectance infrared Fourier transform (DRIFT) techniques. The characterization outcomes manifested that the CeVO 4 -CeO 2 nanocomposite could inhibit its crystallinity and enhance the concentrations of chemisorbed oxygen species and Ce 3+ , which was advantageous to the SCR process. Moreover, the in situ DRIFT technique manifested that the NH 3 -SCR reaction over Ce 0.75 V 0.25 O y was enhanced effectively through the mechanism of L-H.

CO pretreatment was found to effectively improve the SCR performance of CeO 2 , with over 90% at about 300 °C. The larger specific area and the decrease of CeO 2 crystallization indicated the modification of the surface structure after CO pretreatment. Abundant Ce 3+ species and active oxygen, better reducibility, and the higher surface adsorption capacity were mainly responsible for its enhanced SCR performance. DRIFT analysis revealed the presumed coexistence of two reaction routes that the L-H mechanism was related to the reaction temperature, while the reaction rate of E-R route was almost directly proportional to the NO concentration at a certain temperature, based on the kinetic calculation. In addition, the CO-pretreated CeO 2 also exhibited a better poisoning tolerance for SO 2 and H 2 O and excellent thermal stability and circularity. Graphical abstract The process of NH 3 -SCR reaction over CeO 2 -CO catalyst.

Z-Scheme MoS2/g-C3N4 heterojunction photocatalysts were fabricated using a hydrothermal deposition procedure together with a calcination route, and then applied for CO2 photoreduction. Experimental results indicated that the 10% MoS2/g-C3N4 heterojunction displayed the best photocatalytic performance. Furthermore, the maximum CO yields of 58.59 μmol (g-cat)-1 under 7 h-visible light irradiation was up to 2.94 times that of the unadulterated g-C3N4. The enhanced photocatalytic performance of 10% MoS2/g-C3N4 catalyst was due to the favored visible light response, the efficient separation of photogenerated electron-hole pairs as well as its larger specific surface area.

It was well recognized that Pb had a poisoning effect on a SCR catalyst. In this study, the deactivation mechanism of Pb on the Ce/TiO 2 catalyst was investigated based on the characterization results of TPD and in situ DRIFT studies. It was found that the addition of Pb on the Ce/TiO 2 catalyst not only inhibited the adsorption and activation of NH 3 species, but also led to the decrease of the activity of adsorbed NH 3 species in the SCR reaction. The adsorption of NOx species and the oxidation of NO by O 2 over the Ce/TiO 2 catalyst were also suppressed by the addition of Pb, while the reactivity of adsorbed NO 2 species did not decrease. Moreover, the results revealed that the NH 3 -SCR reaction over the Ce/TiO 2 catalyst followed both the E-R and L-H mechanisms, while the NH 3 -SCR reaction over Ce/TiO 2 -Pb was mainly controlled by the L-H mechanism. The contributions of the L-H mechanism to the SCR reactions over Ce/TiO 2 and Ce/TiO 2 -Pb decreased with increasing reaction temperature. The deactivation of Ce/TiO 2 -Pb was mainly attributed to the suppressed NH 3 adsorption and activation, accompanied by the inhibited NO oxidation and the decrease of Brønsted acid sites.

CeO2-CuO/Al2O3 catalysts were prepared by three different methods and their activities for selective catalytic reduction (SCR) of NO with NH3 were investigated. As can be seen from the experimental results, the catalyst prepared by the single-step sol-gel (SG) method showed the best SCR activity and resistance to SO2 and H2O. In order to investigate the relationship between the preparation method and the performance of SCR catalysts, the catalysts were characterized by using Brunauer-Emmett-Teller, X-ray diffraction, temperature programmed reduction with hydrogen, temperature programmed desorption with ammonia, X-ray photoelectron spectroscopy, Fourier transform infrared and thermo-gravimetric analysis techniques. It was found that the excellent performance of CeO2-CuO/Al2O3 catalyst prepared by the single-step SG method should be resulted from its large surface area, low crystallinity, high oxygen storage capacity, high NH3 adsorption capacity, high concentration of surface chemisorbed oxygen, weak sulphation process and weak water absorption.