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Highlights: [•] W18O49/TiO2 hybrid achieves significant synergetic promotion on the photoactivity and photostability. [•] W18O49(10wt%)/TiO2 and W18O49(90wt%)/TiO2 show 2.43 (2.64) and 1.31 (1.52) times higher activity than the calculated baseline in degradation of MO (phenol), under UV–vis and visible light, respectively. [•] Well-matched band structure between W18O49 and TiO2 enhances the photo-induced charge separation and transfer. [•] ·O2 − and hole, especially the former, are the active species involved in the photodegradation. [ABSTRACT FROM AUTHOR]

Abstract: The photoisomerization of norbornadiene using M–Ti–MCM-41 (M=V, Fe and Cr) has been studied to develop an alternative for solar energy accumulation and high energy aerospace fuel synthesis. The photocatalysts were prepared via hydrothermal method and characterized by EDX, XRD, N2 adsorption–desorption, TEM, UV–vis, XPS and IR. With the same Si/M ratio in starting materials, the final concentration of V in the photocatalyst is significantly lower than that of Fe and Cr. V5+ and Fe3+ ions are highly dispersed in Si–O framework with tetrahedral coordination when the metal content is low, and the ordered structure is well retained. However, some species in higher coordination and polymerized environments present with increasing metal content, and the ordered structure becomes to collapse. Cr ions are difficult to get into the framework with various species like extraframework Cr6+ and bulk Cr2O3 formed, also the ordered structure is greatly destroyed. Under UV irradiation, the transition metal ions can improve the photoisomerization activity, with the order of V>Fe>Cr. The activities of V– and Fe–Ti–MCM-41 rise with the increase of Si/M ratio, whereas the performance of Cr–Ti–MCM-41 is irregular. The photocatalysts do not exhibit any activity under visible light, regardless of their absorption in visible-light region. The activity is closely related to the extent of dispersion and local structure of metal ions, about which an indirect excitation process of Ti–O species is suggested. [Copyright &y& Elsevier]

Ag 2 O/P25 and Ag/P25 catalysts were synthesized and applied in the photocatalytic reduction of nitrate with formic acid as a hole scavenger. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM) analysis demonstrate that Ag 2 O or Ag nanoparticles were well distributed on the surface of P25. Under UV irradiation, 5% Ag 2 O/P25 showed a fast rate (0.95 h −1 , 6.3 times of P25), a high conversion (97.2%, 3.63 times of P25) and a high N 2 selectivity (83.1%, 1.15 times of P25) for nitrate reduction. The improved separation of electron–hole pairs on Ag 2 O/P25 results in the high conversion of nitrate. Moreover, compared with the Ag/P25 catalyst, Ag 2 O/P25 exhibited a good reusability in nitrate reduction. The formed Ag–Ag 2 O structure [Ag(0) present on the surface of Ag 2 O] over P25 by partial photoreduction of deposited Ag 2 O contributed to the better stability of Ag 2 O/P25 in nitrate reduction. The present study provides a new sight into the use of Ag 2 O/P25 catalyst in the reduction of nitrate. [ABSTRACT FROM AUTHOR]

Developing a one-pot method for tandem hydrogenolysis–hydrogenation of biomass-derived furan-based alcohols to methyltetrahydrofurans is challenging but crucial for synthesizing sustainable biofuels and chemicals. Herein, we report the efficient hydrogenolysis–hydrogenation of furan alcohol to 2-methyltetrahydrofuran using a phosphate-supported synergistic palladium single atom and nanoparticle at an ambient temperature. Comprehensive characterizations and theoretical calculations reveal that in situ H 2 heterolysis at the palladium single atom–AlPO 4 interface generates frustrated Lewis H+–H− pairs, which selectively cleaves the C–OH bond in furan alcohol to form 2-methylfuran, and H atoms on the palladium nanoparticle surface promotes the subsequent C C hydrogenation of 2-methylfuran to 2-methyltetrahydrofuran. Additionally, the catalyst shows generality for various furan and heterocyclic alcohols. Furthermore, the catalyst exhibits excellent activity in the hydrogenation–hydrogenolysis–hydrogenation of furan aldehydes to methyltetrahydrofurans. The results provide a highly efficient reaction for synthesizing methyltetrahydrofurans at ambient temperature, which has excellent potential for industrial applications. [Display omitted] • Phosphate-supported synergistic palladium single atom and nanoparticle was fabricated. • Methyltetrahydrofurans was selectively obtained from tandem hydrogenolysis–hydrogenation of furan alcohols. • In situ H 2 heterolysis-generated H−–Pd–P–O-H+ site over palladium single atom provides the C–OH hydrogenolysis site. • Palladium nanoparticle promotes the subsequent C C hydrogenation. • The catalyst shows generality for various furan and heterocyclic alcohols. [ABSTRACT FROM AUTHOR]

Developing affordable and efficient electrocatalysts toward water electrolysis under industrial conditions is crucial for large-scale production of green hydrogen. In this regard, we propose a facile and mild method to construct crystalline-amorphous composites of metal phosphate (MPi) and NiS on nickel foam (NF) for practical water electrolysis. The as-prepared electrodes exhibit excellent performance, achieving a remarkable current density of 1000 mA cm–2 at the ultralow overpotential of 345 and 223 mV for FePi-NiS/NF (oxygen evolution reaction, OER) and NiCoPi-NiS/NF (hydrogen evolution reaction, HER), respectively. The composites can undergo an in-situ transformation into highly active and targeted species under high current density, which possess a unique pore structure interconnected by nanosheets that provides an abundance of catalytic sites and open channels for efficient bubble diffusion. When operated under industrial conditions (6 M KOH, 70 °C), the assembled electrode requires only 1.712 V to attain a current density of 1000 mA cm−2. The electrodes also demonstrate exceptional performance in alkaline electrolysis with an anion exchange membrane (AEMWE) when scaled up to a larger size (area: ≈ 25 cm2). Specifically, they achieve a substantial current of 12.5 A at 1.87 V with a high energy efficiency of 79.2 % and remarkable durability over 30 h under industrial electrolysis conditions (1 M KOH, 50 °C), outperforming benchmark Pt/C/NF || IrO 2 /NF electrodes with energy saving of 0.215 kWh Nm–3. This work provides a cost-effective and efficient strategy for designing and constructing stable and active catalysts for water electrolysis under harsh industrial conditions. [Display omitted] • Self-supported crystalline-amorphous composites are prepared by a universal method. • FePi-NiS/NF and NiCoPi-NiS/NF exhibit excellent OER and HER performance, respectively. • The in-situ formed active species play an important role in water splitting. • The assembled AEMWE (area: ≈ 25 cm2) can be operated efficiently and stably under industrial conditions. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Metal-defected spinel Mn x Co 3-x O 4 was fabricated by calcining bimetal glycerolates. • A unique Mn-enriched surface results in abundant surface active sites. • Metal defects lead to enhanced electrical conductivity and O 2 adsorption ability. • Mn 1.5 Co 1.5 O 4 exhibits superior performances in ORR and Zn-air battery. Abstract Manganese-cobalt spinel oxides are considered as a class of promising and low-cost electrocatalysts for oxygen reduction reaction (ORR), whose performances largely depend on their electronic structures which can be effectively optimized by defect engineering. Herein, metal defects (manganese vacancies and cobalt vacancies, i.e. V Mn and V Co) were in-situ introduced into spinel Mn x Co 3-x O 4 via a simple solvothermal treatment followed by thermal calcination. Mn-Co glycerolate precursors not only enable controllable synthesis of spinel oxides with variable metallic ratios, but also play a key role in constructing metal defected crystals for their lamellated structure. As a result of the formation rate difference between manganese and cobalt glycerolate, a unique Mn-enriched surface is formed, leading to the increase of highly active sites for ORR. Importantly, the presence of metal defects, confirmed by XRD (X-ray diffraction), element analysis and XAFS (X-ray absorption fine structure spectroscopy), leads to greatly increased electrical conductivity and O 2 adsorption ability, thus bringing about enhanced ORR activity. Especially, metal-defected Mn 1.5 Co 1.5 O 4 , with the optimal Mn/Co ratio, exhibits comparable activity and superior durability to those of the benchmark Pt/C in ORR and displays excellent discharge performance in Zn-air batteries for practical application. This work provides a new way to optimize the electrocatalytic performance of mixed metal spinel oxides via rational defect engineering. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Pt decorated Ni(OH) 2 composite is highly effective in activating and cleaving H 2 O. • The composite is in-situ grown on semiconductors via photoinduced deposition. • Pt/Ni(OH) 2 -C 3 N 4 achieves an AQE of 1.8% at 420 nm in overall water splitting. • Pt/Ni(OH) 2 enables TiO 2 to split pure water. Abstract Photocatalytic overall water splitting is one of the ultimate goals in solar conversion and the activation and cleavage of H 2 O molecule is the initial and often rate-determining step in this reaction. Through DFT calculations, we designed Pt cluster decorated Ni(OH) 2 nanoparticles (Pt/Ni(OH) 2) as robust cocatalyst capable of activating H 2 O and dissociating HO H bonds. Then the unique structure was fabricated through in-situ photo-oxidation of Ni 2 P to Ni(OH) 2 on semiconductor like C 3 N 4 and subsequent selective photo-deposition of Pt on Ni(OH) 2 surface. Pt/Ni(OH) 2 -C 3 N 4 is much more active in photocatalytic HER, OER and overall water splitting compared with Pt, Ni(OH) 2 and spatially separated co-loaded Ni(OH) 2 -Pt on C 3 N 4. And Pt/Ni(OH) 2 -C 3 N 4 achieves an AQE of 1.8% at 420 nm in overall water splitting by using only 0.3 wt% Pt, superior to most solid-state photocatalytic systems to date. Moreover, Pt/Ni(OH) 2 composite enables TiO 2 to split pure water in good stoichiometry. This work emphasizes the importance of H 2 O activation and may pave the way for enabling single semiconductors to efficiently split pure water. [ABSTRACT FROM AUTHOR]

Upgrading lignocellulosic ketones to Jet fuel precursors by aldol condensation is the key step for the synthesis of high-grade bio-Jet fuels. State-of-art works are confined in pure feedstock used, catalysis sites leaching and coking. Therefore, we synthesized a strong solid acid HfTPA/MCM-41 and used it to catalyze aldol condensation of lignocellulosic ketone mixture to bio-jet fuel blending precursors, where 80 %Hf 1.5 TPA/MCM-41 shows better activity than 80 %HPW/MCM-41 and commercial zeolites with 66.8 % yield of products obtained. The good performance of the catalyst is ascribed to good acid properties, large surface area and especially new strong L acids and good stability based on anti-coking and water tolerance by Hf doping, which changes the electronic structure of the catalyst surface to efficiently activate C O bond of ketones to form a metal enolate intermediate and anchoring HPW from leaching. This work demonstrates an efficient way to synthesize high-performance acid catalyst applied in bio-jet fuel synthesis. [Display omitted] • A good-performance strong solid acid catalyst with new strong L acid and good stability was synthesized. • The good-performance of the catalyst is attributed to the Hf doping. • This catalyst was simply synthesized by combination of equivalent-volume impregnation and co-deposition. • High-performance bio-jet fuel blending precursors were synthesized using lignocellulosic derivatives ketones. [ABSTRACT FROM AUTHOR]

Photocatalytic water oxidation suffers from sluggish kinetics and remains the bottleneck for water splitting. Here, using CeO 2 nanorods as model photocatalyst we studied the critical role of oxygen vacancies in photocatalytic water oxidation. First CeO 2 nanorods with similar morphology but different concentration of oxygen vacancies were fabricated by one-step hydrothermal method with in-situ reducing treatment. The optical absorption, charge transfer efficiency, and photocatalytic activity in oxygen generation were found closely dependent on the concentration of oxygen vacancies. Then density functional theory calculations were conducted to unveil the role of oxygen vacancies and understand the water oxidation mechanism. It was found the presence of oxygen vacancies narrows the bandgap and modulates the electronic structure for accelerating the charge transfer, in good agreement with the experimental observations. The overall oxygen generation pathway was screened and the oxygen vacancies were found to lower the barrier energy for the rate limiting step of O O bond formation and restrain the reverse reaction of O and H, thus the O 2 generation kinetics on oxygen-defective CeO 2 are improved significantly. This study provides in-depth understanding on the critical role of oxygen vacancies in photocatalytic water oxidation and is helpful for designing highly efficient photocatalyst to overcome the bottleneck of water splitting. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C 3 N 4 ) has emerged as a promising photocatalyst, but poor charge separation and low surface area limit its activity. Here, we report a hydrothermal method to generate hydrogen bonded supramolecular complex via water-based homogeneous supramolecular assembly, which is a promising precursor to fabricate porous and oxygen-doped g-C 3 N 4 . The hydrothermal treatment provides a homogeneous environment for hydrolysis of melamine to produce cyanuric acid and reaction of cyanuric acid with remained melamine to create the in-plane ordering and hydrogen bonded supramolecular complex. The complex can template uniform nanoporous structure and also provide an opportunity for O-doping in the g-C 3 N 4 network upon calcination in air. The resulted g-C 3 N 4 (GCN-4) possesses high surface area, well-defined 3D morphology and oxygen-dopant in the lattice. Subsequently, the visible light absorption, charge separation, and wettability are considerably enhanced. This catalyst exhibits higher hydrogen evolution rate by 11.3 times than the bulk g-C 3 N 4 under visible light irradiation, with apparent quantum efficiency of 10.3% at 420 nm. [ABSTRACT FROM AUTHOR]

The utilization of solar energy into photoelectrochemical (PEC) water splitting is a popular approach to store the sustainable energy and minimize the dependence of fossil fuels. Herein, multi-layer BiVO 4 films were synthesized by multi-cycle electrodeposition following by annealing at high temperature. Multi-layer BiVO 4 films have monoclinic scheelite structure, and the morphology is changed from densely compact film to sponge-like network, and then bulk structure with the increase of electro-deposited layers. X-ray photoelectron spectra indicate the presence of abundant oxygen vacancies and V 4+ species in multi-layer BiVO 4 , especially for 3-layer one. For visible-light PEC performance, 3-layer BiVO 4 shows the highest photocurrent among the samples, i.e. up to 5.80 mA/cm 2 in sulfite oxidation and 1.79 mA/cm 2 in water splitting at 1.23 V versus a reverse hydrogen electrode (RHE) under 1 sun irradiation (100 mW/cm 2 ), with very high IPCE achieved nearly 83% and 25% (at 420 nm), respectively. The extremely high PEC performance of 3-layer BiVO 4 is attributed to its morphology of sponge-like network and the modulated band structure by the oxygen vacancies and V 4+ species. Moreover, the multi-layer BiVO 4 also shows very high photostability. This work provides a multi-layer-construction method for highly visible-light-active PEC anodes for practical applications. [ABSTRACT FROM AUTHOR]

Direct Z-scheme photocatalyst, which enables efficient charge separation and retains high redox ability, is promising material for visible-light-driven hydrogen evolution. Here we developed a one-step solvothermal method to fabricate direct Z-scheme CdS/CdWO 4 composite via treating W 18 O 49 with CH 3 CSNH 2 and Cd(CH 3 COO) 2 . By controlling the dosage of Cd(CH 3 COO) 2 , CdS nanoparticles decorated CdWO 4 nanowires (CS-2) is synthesized. UV–vis DRS and XPS spectra demonstrate that the CdWO 4 possesses a large amount of oxygen vacancies, which help to form ohmic contact and broaden light absorption. Compared with CdS, CS-2 Exhibits 18 times higher visible-light H 2 evolution activity using lactic acid as sacrificial agent and shows 7.8-fold higher photocurrent density. Moreover, photoelectrochemical test manifests the efficient separation of the photo-induced charge carriers. Radical-trapping experiments along with in-situ Pt photodeposition further prove that the charge transfer and separation follows Z-scheme mechanism. This work highlights the critical role of defects in the formation of direct Z-scheme composite. [ABSTRACT FROM AUTHOR]

Herein, an efficient domino synthesis for N-aryl pyrroles and tetrahydropyrroles from biomass-derived furan alcohols (i.e., 5-methyl furfuryl alcohol, and 2,5-bis(hydroxymethyl)furan) and nitrobenzenes was reported for the first time over metal phosphides. Dual active sites, including metal sites for nitro hydrogenation, acid sites for furan alcohol ring-opening determine the catalytic performance. Different from traditional tandem catalysts of Pd/C and HZSM-5 or Amberlyst-15 that suffer from binary competitive adsorption of furan and nitro groups on metal sites, as well as hydroxyl and hydrogenated amino groups on the acidic sites, metal phosphides show unexpected cooperative catalytic properties with the oriented synthesis of pyrroles over NiCoP and tetrahydropyrroles over Ni 2 P. Furthermore, the catalyst displays outstanding stability and recycling performance after 4 runs. This work demonstrates an effective strategy for governing reaction routes by selective activation and shows the powerful synergistic effect of hydrogenation and acid catalysis. [Display omitted] • A series of metal phosphides (NiCoP, Ni 2 P, Co 2 P) were prepared. • N-aryl pyrroles were obtained from furan alcohols and nitrobenzenes over NiCoP. • N-aryl tetrahydropyrroles were obtained over Ni 2 P. • Selective hydrogenation and acid activation ensure the synergistic catalysis. • The catalysts show excellent recycling stability. [ABSTRACT FROM AUTHOR]

ZnO is an important semiconductor that has been widely applied in solar cell, photocatalysis, environmental remediation. Doping and morphology control are important approaches to improve its photocatalytic performance. Herein, a facile two-step calcination method was developed to fabricate carbon(C)-doped cubic ZnO with porous structure from zeolite imidazolate frameworks (ZIF-8). Compared with one-step pyrolysis, the approach of two-step calcination not only retains the cubic morphology with inter-connected ZnO nanoparticles and porous structure but also introduces C doping in ZnO lattice effectively. This morphology has advantage in charge transfer, optical absorption and mass transfer during the photoreaction, and C doping results in high charge-separation efficiency. The sample C350-400 (C-doped ZnO, firstly calcined at 350 °C for 2 h from ZIF-8, then 400 °C for 1 h) shows the maximum photoactivity, which is ca . 3-fold and 4-fold higher than ZnO (C450) in photodegradation and PEC water splitting (under UV–vis irradiation), respectively. It is expected that the preparation of metal oxide from MOF is a very promising way to fabricate highly efficient photocatalyst. [ABSTRACT FROM AUTHOR]

Composites having both maximized adsorption capability and high photocatalytic activity are very promising for pollutant removal by combining adsorption and photocatalysis. In this work, we report a facile sonochemical synthesis of Cu 2 O(nanoparticles)/Cu 2 (OH) 3 NO 3 (sheets) composites with tunable composition using only copper powders and Cu(NO 3 ) 2 as precursors. The composites can be controlled from almost pure Cu 2 O (98.1%) to pure Cu 2 (OH) 3 NO 3 (95.9%) through adjusting the initial ratio of Cu 2+ :Cu 0 and sonication time. Controlled experiments show that Cu 2 O nanoparticles are formed first via the redox reaction between Cu 2+ and Cu 0 , after that Cu 2 O are converted to Cu 2 (OH) 3 NO 3 . Cu 2 (OH) 3 NO 3 synthesized using the sonochemical method exhibits outstanding adsorption capability toward organic dyes, subsequently Cu 2 O can degrade them quickly via photocatalysis, so the Cu 2 O/Cu 2 (OH) 3 NO 3 composites are very efficient to remove pollutant due to the synergetic effect of adsorption and photocatalysis. In particular, composite with 30.6% of Cu 2 (OH) 3 NO 3 and 69.4% of Cu 2 O shows the highest removal capability and good stability. [ABSTRACT FROM AUTHOR]

A hollow bimetallic CoFe 2 O 4 nanocube rationally modulated by carbon wrapper and oxygen vacancy demonstrates an overwhelming synergetic effect, achieving superior activity, stability and durability towards electrochemical nitrogen reduction reaction under ambient conditions. [Display omitted] • Hollow C@CoFe 2 O 4-x nanocube is devised and proposed as novel NRR electrocatalyst. • PBA-derived CoFe 2 O 4 nanocube demonstrates great intrinsic activity. • Carbon wrapper and oxygen vacancy are introduced via facile strategies. • Prominent synergy effect ensures superior activity, selectivity and durability. Electrocatalytic nitrogen reduction reaction is increasingly deemed as a promising route for massive ammonia synthesis. Herein, hollow bimetallic CoFe 2 O 4 nanocube derived from prussian blue analogue is elaborately wrapped by thin carbon layer and modified by rich oxygen vacancies, achieving splendid ammonia yield rate of 30.97 μg h−1 mg cat. −1 and Faradaic efficiency of 11.65 % at −0.4 V versus reversible hydrogen electrode in 0.1 M Na 2 SO 4. In addition, C@CoFe 2 O 4-x nanocube can withstand long-term and repetitive electrolysis without obvious structure collapse, constituent change and activity decay. The prominent activity is strongly associated with improved nitrogen adsorption and activation, collaboratively benefiting from the intrinsic unoccupied d orbitals of transition metal components, reformative electronic structure by oxygen vacancies and elevated electron injection possibility into the antibonding orbital of nitrogen molecule via conductive carbon wrapper. Both actual experiments and theoretical investigations attest the catalytic activity improvement mechanism, rendering the C@CoFe 2 O 4-x nanocube design strategy efficient and valid. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of high-performance bio-jet fuel by directly making fuel blending. • Making jet fuel blending using lignocellulosic derivatives as feedstock. • Develop an efficient catalyzing and energy-saving method of synthesis of jet fuel blending by co-conversion of biomass mixture. Bio-jet fuel synthesis is a promising way to upgrade the value of lignocellulose and contributes to the sustainable development. Presently the property of bio-jet fuel is weakened by single component produced using pure feedstock and water produced in the reaction leading to acid leaching. Therefore, we synthesized a hydrophobic acid resin (R-x) and used it to catalyze lignocellulose-derived mixture upgrading to high-performance bio-jet fuel blending, where R-x shows better activity than Amberlyst-15, Nafion-212 and Hβ with 75.4% of product yield obtained in co-conversion of lignocellulosic derivatives. The better activity of R-x is ascribed to the strong acid, big acid concentration, large surface area and especially super hydrophobicity resulting as R-x recycled steadily in consecutive 5 runs. After hydrodeoxygenation, jet fuel blending with high density and excellent freezing point better than JP-7 was obtained. This work demonstrates an efficient catalyzing method to synthesize high-performance jet fuel by co-conversion of lignocellulosic derivatives. [ABSTRACT FROM AUTHOR]

• Amorphous NiO x brings unique urbach tail absorption in near infrared region. • The disorder feature gives rich active site to boost rate-limiting water oxidation. • Ultrathin structure and external electron capture greatly prolong carrier lifetime. • It enlightens pure water splitting up to 680 nm with an AQE of 6.2 % at 420 nm. Harvesting near infrared light for water splitting opens up a new avenue in solar conversion but suffers from the low photon energy. Towards this, amorphous a-NiO x is reported to exhibit strong long-wavelength urbach tail absorption and provide abundant oxidation active sites due to its disordered structure. And its intrinsic two-dimensional ultrathin structure shortens the migration distance of photoinduced carriers. This enlightens water splitting under 680 nm red light when combined with electron captures like reduced graphene oxide. Furthermore, a-NiO x ||C 3 N 4 heterojunction is constructed to extend the light response from UV to near infrared region, together with a built-in-electric field to facilitate interfacial charge separation. The unique structure achieves stoichiometric water splitting under simulated sunlight with an apparent quantum efficiency of 6.2 % at 420 nm, outperforming most state-of-art photocatalysts. This work may bring new opportunities in modulating amorphous materials for artificial photocatalysis. [ABSTRACT FROM AUTHOR]

• Mn-defected Mn 3 O 4 was synthesized by thermal oxidation of manganese glycerate. • Mn defects tune electronic delocalization to improve conductivity. • Mn defects result in more surface Mn3+ as major active site. • O 2 activation and OH* desorption are facilitated by Mn defects. • Mn defects reduce the Gibbs free energy variation in the rate-limiting step. Manganese-based oxides are promising in electrocatalytic oxygen reduction reaction, but the activity and conductivity need further improvement. Herein manganese defected Mn3O4 was fabricated by solvothermal synthesis of manganese glycerate and then thermal calcination. The experimental and computational results reveal that manganese defects in Mn3O4 modify the electronic structure to improve conductivity and electronic delocalization, which helps to expose more surface Mn3+ as major active site, thereby facilitating O2 activation and OH* desorption, and reducing the Gibbs free energy variation in the rate-limiting step of ORR. Accordingly, the onset potential, half-wave potential and limiting current density of manganese defected Mn3O4 are 0.87 V, 0.65 V and 5.0 mA cm-2, better than that of normal Mn3O4 (0.77 V, 0.62 V and 2.6 mA cm-2). This work provides an effective approach to tune the defects and electronic structures of Mn3O4 for better electrochemical activity. [ABSTRACT FROM AUTHOR]

• The solid-acid structure was introduced on surfaces of Co 3 O 4 and CoNiFeO x. • The SO 4 2− modification triggers Co4+ and intermediate spin state of Co3+ (t 2 g 5 e g 1). • Additional adsorption of SO 4 2− breaks adsorption-energy scaling relation. • CoNiFeO x -SO 4 exhibits superior performances in OER. Adjusting the electronic structure of electrocatalyst active sites can optimize the adsorption of intermediates to boost the kinetics of oxygen evolution reaction (OER), while this modulation is limited by adsorption-energy scaling relations of three intermediates (*OH, *O and *OOH). This work introduced the solid-acid structure into electrocatalysts through surface bonding SO 4 2− (like Co 3 O 4 and CoNiFeO x). DFT calculations reveal the essence of solid acid modification is that triggers the production of Co4+ and intermediate spin Co3+ (t 2 g 5 e g 1), then lifts metal d-band level and oxygen p-band level. Notably, the hydrogen bonding between SO 4 2− group and ∗OOH provides additional adsorption contribution, thereby breaking the adsorption-energy scaling relation of OER. Modified by SO 4 2−, the CNF-SO 4 shows remarkably high performance with overpotential of 231 mV (at 10 mA cm-2) and low Tafel slop of 33.8 mV·dec-1. This work provides an effective solid-acid-mediated strategy for electronic structure regulation and adsorption-energy scaling relation breaking in OER. [ABSTRACT FROM AUTHOR]

• NiCoP/TiO 2 sensitized system is constructed by tuning the band structure of NiCoP. • NiCoP sensitizes TiO 2 under visible light to form unbalanced charged surface. • The unbalanced charged surface enhances the activation of B–H and H–O bonds. • H 2 evolution rate is enhanced to 3 folds compared with dark reaction. • Full range visible light can be used. Hydrolysis of ammonia borane is promising for instantaneously supplying hydrogen with moderate temperatures. Herein, we utilize NiCoP/TiO 2 sensitized system to construct a highly unbalanced charge distribution for rapid H 2 generation under visible light. The key point is optimizing the band structure to ensure electron injection from NiCoP to TiO 2 because Ni 2 P and CoP cannot form this structure. Under visible light NiCoP is excited and inject electron to TiO 2 , generating a highly unbalanced but stable charge distribution. The positively and negatively charged NiCoP and TiO 2 serve as activation sites for NH 3 BH 3 and H 2 O, respectively. The H 2 generation rate is increased from 0.18 mL/s in darkness to 0.36 mL/s under visible light, with E a reduced from 52.76 kJ/mol to 25.89 kJ/mol. After modifying TiO 2 with 2.5%Pt, the reaction is further increased to 0.55 mL/s. Full visible light can promote the reaction, with each photon trigger two NH 3 BH 3 molecules for reaction. [ABSTRACT FROM AUTHOR]

• Direct Z-scheme ZnO-WO 3- x was constructed by in-situ solvothermal treatment. • Suitable band structure and Fermi level drive the formation of Z-scheme structure. • Stirring leads to piezoelectric polarization of ZnO, and enhances Z-scheme effect. • Zn-W-5 shows very high piezoelectric-photoelectrochemical activities. Photosynthesis with Z-scheme charge transfer has been recognized as an efficient pathway to achieve solar-energy conversion. Herein, the all-solid-state direct Z-scheme ZnO-WO 3-x nanorod arrays were synthesized by in-situ solvothermal treatment for highly piezoelectric (PE)-photoelectrochemical (PEC) water splitting. The chemical bonding between WO 3-x and ZnO via W-O-Zn and the inherent band structures/Fermi levels drive the formation of direct Z-scheme charge-transfer pathway. Importantly, the optimized structure (Zn-W-5) shows higher PEC activities with high photocurrent density of 2.39 mA/cm2 at 1.23 V vs. RHE, which is 2.13 times higher than pure ZnO. Surprisingly, the obvious PE polarization of ZnO increases its Fermi level toward conduction band and significantly enhances Z-scheme effect between ZnO and WO 3-x. Especially, the best sample (Zn-W-5-1000 rpm) shows a photocurrent of 3.38 mA/cm2 at 1.23 V vs. RHE, which is 3.02 times higher than pure ZnO. This work provides a facile PE polarization approach for enhancement of Z-scheme charge-transfer process. [ABSTRACT FROM AUTHOR]

• All-in-one Pt·Ni(OH) 2 /C 3 N 4 photocatalyst realizes one-step overall water splitting. • Pt·Ni(OH) 2 /C 3 N 4 achieves a prominent AQE of 4.2% at 420 nm and excellent stability. • Both H 2 O activation and charge transfer are dramatically enhanced. • The backward recombination of H 2 and O 2 is suppressed. Overall water splitting is vital in solar-hydrogen conversion. In addition to charge separation, the regulation of surface kinetics and suppression of backward reaction become particularly crucial. Herein, an all-in-one Pt·Ni(OH) 2 /C 3 N 4 photocatalyst is proposed by integrating Pt@Ni(OH) 2 composited nanowires and isolated Pt clusters on C 3 N 4. In this heterostructure, Pt@Ni(OH) 2 with rich coordinatively unsaturated sites effectively boost O 2 evolution, and Pt-O-Ni interaction retards O O bond cleavage thus inhibiting backward H 2 O regeneration. Meanwhile isolated Pt forms an Schottky junction with C 3 N 4 for electron transfer and proton reduction. Consequently, Pt·Ni(OH) 2 /C 3 N 4 achieves stoichiometric water splitting with H 2 /O 2 evolution of 1330/632 μmol g−1 h−1, and an outperforming AQE of 4.2% at 420 nm. Our work manifests that accelerating charge migration, inhibiting backward reaction and tuning surface kinetics are dominant in water splitting, for which a rational design of robust redox pathways is necessary. [ABSTRACT FROM AUTHOR]

• MnO x -decorated 3D porous C 3 N 4 is fabricated by NaCl-templated method. • C 3 N 4 possesses donor–acceptor system by Na ions and cyano groups. • MnO x modulate holes transfer and provide oxidation sites. • C 3 N 4 shows quick charge separation and stronger reduction capability. • C 3 N 4 achieves 18-fold higher H 2 production rates of bulk C 3 N 4 under visible light. Carbon nitride is an intriguing visible-light photocatalyst for H 2 production but suffers from low surface area and fast charge recombination. Here, we report a simple yet efficient approach to fine tune the porous structure, modify the electronic structure and carrier behaviors of C 3 N 4 through in-situ growth of MnO x by NaCl template-assisted strategy. This NaCl template method simultaneously constructs 3D porous structure for high surface area, induces Na coordination with N atoms and accompanying cyano group to form an internal donor-acceptor system for efficient charge transfer and separation. Along with the MnO x growth, the band gap of C 3 N 4 is narrowed for stronger visible light absorption and the conduction band level is negatively shifted for stronger reduction capability. Thus, the resulted C 3 N 4 (MSCN) shows much improved activity of about 18 times higher than bulk C 3 N 4 in photocatalytic hydrogen evolution reaction under visible light irradiation. [ABSTRACT FROM AUTHOR]