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In recent years, the greenhouse effect has emerged as a major environmental concern. As a result, the utilization and capture of greenhouse gases have become urgent tasks. The dry reforming of methane (DRM) reaction is a technology that directly converts greenhouse gases (CH4 and CO2) into valuable products. Ni-based catalysts have gained significant attention and industrial prospects in DRM reactions due to their excellent performance and cost-effectiveness compared to noble metals. However, challenges such as metal sintering and carbon deposition hinder its industrialization. This paper provides a review of the recent advancements in catalyst design for DRM reactions, with a focus on the impact of additives, supports, and preparation methods on Ni-based catalysts. It also describes the reaction and deactivation mechanisms, as well as the thermodynamics and kinetics of DRM reactions. Furthermore, this paper envisions the main challenges and opportunities associated with Ni-based catalysts in DRM research. [ABSTRACT FROM AUTHOR]

An orthogonal experiment design was adopted for synthesis and optimization of ZrO2-Based catalyst for coke oven gas CO shift. The influence of the operating parameters on catalytic properties was investigated, with a composition being similar to typical industrial heterogeneous catalysts for WGS process. The experimental CO conversion data was analyzed by marginal and variance analysis. The optimal operating parameters for ZrO2-Al2O3based catalyst were suggested by CO conversion. [ABSTRACT FROM AUTHOR]

Dry reforming of methane (DRM) is an effective method for achieving carbon reduction and carbon neutrality by directly converting two greenhouse gases, CH 4 and CO 2 , into value-added products. However, catalysts used in this process are prone to metal sintering and carbon deposition, which are major obstacles. Thus, the design of high-performance catalysts is crucial for the success of dry reforming technology. In this paper, a series of Co-based catalysts modified with different rare earth metals (Y, Tb, Gd) and γ-Al 2 O 3 as the support were prepared using the conventional co-impregnation method. The effects of the introduction of rare earth metals additives on the activity and resistance to carbon build-up of the catalysts were investigated. The catalysts were analyzed using various characterization techniques. The results showed that Y and Tb as additives could effectively improve the activity and stability of the catalyst. However, the Gd modified Co-based catalyst had a large specific surface area but was less favorable for the DRM reaction. The best performance catalyst was achieved with the 10Co–5Y/γ-Al 2 O 3 under 750 °C with CH 4 and CO 2 conversions of 91.79% and 98.33%, respectively. This is mainly due to the fact that the introduction of Y enhances the electron transfer between Co and metal oxides, generating more oxygen vacancies and base vacancies on the surface, thus enhancing the adsorption and activation of CO 2. The 10Co–5Y/γ-Al 2 O 3 catalyst demonstrated excellent DRM performance even after 20 h at 750 °C. Moreover, we proposed a hypothesis regarding the mechanism of resistance to carbon build-up. This study provides a reasonable idea to design Co-based catalysts with resistance to sintering and carbon accumulation to improve the performance of reforming catalysts. [Display omitted] • The introduction of Y and Tb enhances the electron transfer ability of Co species. • The introduction of Y improves the cobalt dispersibility and oxygen vacancies. • 30% enhancement in CH 4 and CO 2 conversion was achieved with 10Co–5Y/γ-Al 2 O 3. • The mechanism of resistance to carbon build-up was proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effect of lanthanide metal oxides on the carbon deposition resistance was studied. • Lanthanide metal oxides increase the surface oxygen vacancies and basicity of the catalyst. • Lanthanide promoters reduce the degree of graphitization of carbon deposits. • The kinetics of DRM catalysts with different promoters were studied. • Catalysts added with lanthanide promoters follow a bifunctional reaction mechanism. Dry reforming of methane (DRM) can well convert CO 2 and CH 4 into syngas to further synthesize valuable chemicals, thereby realizing the resource utilization of greenhouse gases. However, the sintering and carbon deposition vulnerabilities of Ni-based dry reforming catalysts prevent them from being commercialized. The ethylene glycol impregnation method was used in this study to create a group of Ni/MSS catalysts added with lanthanide metal oxides (CeO 2 、La 2 O 3 、Sm 2 O 3 、Nd 2 O 3). A range of characterization techniques were employed to examine the impact on the resistance to carbon deposition and sintering. Studies have shown that lanthanide metal oxides enhance the metal support interaction, promote active metal Ni dispersion and reduce Ni particle size. Meanwhile, the catalyst's alkali strength and basic site count both rise, and a large number of surface oxygen vacancies are produced, among which CeO 2 has the most obvious effect. As a result, the catalyst's activity and resistance to carbon deposition and sintering are greatly increased, while also inhibiting the degree of graphitization of carbon deposition. According to the kinetic studies, the catalyst containing lanthanide metal oxides had an apparent activation energy for CH 4 and CO 2 that was lower than the Ni/MSS catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electronegativity of the A species in ACu-CeO 2 affect catalytic activity for CO-SCR reaction. • CuCo-CeO 2 exhibited 100% NO conversion and 100% N 2 selectivity in CO-SCR. • The addition of species A promotes the electron/ion transfer between metals in the catalyst. • The CO-SCR reaction mechanisms was proposed based on in situ DRIFTS. Transition metal-based nanomaterials have gained significant attention as highly active and cost-effective catalysts for the selective catalytic reduction (SCR) of NO with CO. Using a simple wet impregnation method, the catalyst composition and active sites can be modulated. In this paper, we present a novel cerium-based co-solvent catalyst, A-site doped ACu-CeO 2 (A = Co, Fe, Mn), for CO-SCR of NO. The doping of A-site elements induces structural changes and enhances catalytic performance. Among the doped catalysts, CoCu-CeO 2 exhibits a wide temperature window for operation and high selectivity towards nitrogen, achieving 100% NO conversion at 200 °C. Furthermore, A-site modulation not only promotes electron/ion transfer within the catalyst but also enables uniform and dispersed distribution of the active metal species, particularly copper, in the CoCu-CeO 2 catalyst. This provides reaction centers for the selective reduction of NO by CO and enhances the adsorption capacity of the catalyst for NO. The ACu-CeO 2 catalyst demonstrates excellent CO-SCR catalytic performance and resistance to vapor. Characterization techniques such as XPS, Raman spectroscopy, and in situ DRIFTS elucidate the reaction mechanism of the ACu-CeO 2 cerium-based co-solvate in the CO-SCR reaction. This study furthers our understanding and improvement of catalyst design, while also providing an efficient and straightforward denitrification catalyst for controlling air pollutants. [ABSTRACT FROM AUTHOR]

[Display omitted] • Additional defects were developed from N incorporation-evaporation. • Defects favor the generation of active sites of Co. • The established defects promoted the adsorption and activation of CO 2. • The anchoring and electronic effects of defects in Co elevated catalytic activity. Dry reforming of methane (DRM) is gaining interest as an environmentally-friendly method for converting greenhouse gases into valuable H 2 /CO feedstock. However, catalyst deactivation due to carbon deposition and active metal sintering poses a challenge. Herein, defect-rich biomass carbon materials are obtained in a simple way. Under the combined effect of high temperature and defect inducers, the evaporation of N atoms introduced to the carbon skeleton and intrinsic N atoms in the biomass leads in the production of defective structures. Further, defect-confined Co catalysts (Y-NC(Z)-20Co) for DRM were reasonably designed and developed using defective biomass carbon as support. It was found that the structure-limiting effect of defective structures prevented the aggregation of Co. Meanwhile, the unpaired electrons of defective structures not only enhanced the basicity of the support to promote the adsorption and activation of CO 2 , but also improved the electronic environment of the anchored Co sites. This enhanced interaction between metal and carbon material, while the electron-rich Co sites promote the adsorption and activation of CH 4. The improved CO 2 activation capacity of Y-NC(Z)-20Co catalyst effectively inhibited the formation of graphitized carbon deposits during the reaction. Thus, defect-rich biomass carbon catalysts made from external N incorporation-evaporation exhibited superior coke-resistance and sinter-resistance. [ABSTRACT FROM AUTHOR]

Dry reforming of methane (DRM) is considered a promising process to convert CH 4 and CO 2 into syngas for achieving carbon neutrality. However, sintering and carbon deposition of Ni pose significant challenges to the industrialization of DRM. The size of Ni particles significantly affects the generation of carbon deposits. In this study, a series of Ni/MSS catalysts were prepared using four different methods, including common impregnation, glycine-assisted impregnation, ethylene glycol-assisted impregnation and ammonia evaporation. The effects of preparation methods on the anti-sintering and anti-coking properties were explored through various characterization techniques. Results showed that glycine-assisted impregnation and ethylene glycol-assisted impregnation effectively improved the dispersion of Ni, resulting in small Ni particles while preserving the unique pore structure of MSS supports. Smaller Ni particles expose more active sites, which facilitate the resistance to carbon accumulation. These catalysts show the highest activity and excellent stability. The catalyst prepared by ammonia evaporation showed the best stability due to the synergistic effect of the strongest basicity and metal-support interaction. However, nickel phyllosilicate generation consumed a small amount of MSS, resulting in reduced specific surface area. Compared with the common impregnation method, the other three methods reduced the particle size of Ni and improved the interaction between support and metal, effectively enhancing the ability of the catalyst to resist coking and sintering. Kinetic studies also showed a significant decrease in the apparent activation energy of methane and carbon dioxide cracking due to the reduced particle size of Ni particles. [Display omitted] • The effect of the preparation method on the performance of the DRM catalyst was studied. • Glycine-assisted and ethylene glycol-assisted impregnation minimize the particle size of Ni particles. • The ammonia evaporation method improved the metal-support interaction and alkalinity. • The small Ni particles of the catalyst suppress the generation of carbon deposits. • The kinetics of DRM catalysts prepared by different methods were investigated. [ABSTRACT FROM AUTHOR]

The selective catalytic oxidation of ammonia (NH 3 -SCO) is currently the most effective method used to eliminate NH 3. However, one of the major challenges for NH 3 -SCO is the development of catalyst capable of completely converting NH 3 into harmless N 2 and water vapor. In this paper, a high N 2 selective catalyst prepared by the sol-gel method using TiO 2 as the support, Cu as the active species, and Sm as the auxiliary agent is presented. Compared to traditional Cu/TiO 2 catalyst, the 4SmCu/TiO 2 catalyst has higher catalytic activity and N 2 selectivity at low temperatures. The NH 3 conversion can reach 100%, and the selectivity of N 2 can be maintained at 100% at 275 °C. The excellent catalytic activity is attributed to the highly dispersed active species, abundant Lewis acid sites (LASs), and the generation of large amounts of surface-adsorbed oxygen. In addition, doping Sm species will cause TiO 2 lattice distortion, and at the same time load the distorted TiO 2 with more active material. Moreover, in-situ DRIFTS analysis suggests that both the 4SmCu/TiO 2 and Cu/TiO 2 catalysts follow the "internal" selective catalytic reduction (iSCR) mechanism during NH 3 -SCO reactions. The 4SmCu/TiO 2 catalyst generates more amides (-NH 2), which reduces the non-selective oxidation of the catalysts and promotes the formation of N 2. This provides a new idea and method for the selective catalytic oxidation of NH 3 to N 2 and water vapor using Cu-based catalysts. [Display omitted] • 4SmCu/TiO2 catalyst converts all NH3 into N2 and water vapor at 275 ℃. • The lattice distortion of TiO2 can support more active species. • Doping of Sm species increased the content of Lewis acid site and surface-adsorbed oxygen. • The rich amide intermediates reduce the non-selective oxidation of NH3 and O2. [ABSTRACT FROM AUTHOR]