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Hydrogenation of nitroaromatics is typically performed under harsh reaction conditions, which would bring safety issues and energy waste. The key for the hydrogenation reaction is to finely control...

Large size and high efficient nanoporous BiVO4 photoelectrode was prepared through a simple printing-like electrochemical synthesis method. The prepared BiVO4 electrode was applied to split water to produce O2 and H2 in a three-electrode system under the irradiation of simulated solar light. NiOOH as cocatalyst was deposited by photo-electrodeposition method to improve the photoelectrochemical (PEC) performance of BiVO4 photoanode. Results reveal that NiOOH can enhance the photocurrent density and lower the over potential of water oxidation reaction. IPCE measurements were used to evaluate solar energy conversion efficiencies of BiVO4 photoanode and BiVO4/NiOOH photoanode. These two kind electrodes showed 17% and 24% IPCE in water splitting reaction. Furthermore, the prepared large size photoanode was proved to have good stability for water splitting. Our study raises the feasibility of fabrication of large size photoelectrode with high efficiency for practical application.

In this work, we employed Yb3+ and Er3+ ions doped in a narrow bandgap oxide Bi20TiO32 to fabricate Bi20TiO32:Yb,Er, which can achieve near-infrared (NIR) responsive upconversion (UC) photocatalysi...

In this paper, n-type Ag2ZnSnS4 (AZTS) thin film was prepared by a simple electrodeposition and in situ sulfurization method on Mo-mesh substrate. Pristine AZTS photoanode yielded a photocurrent density of 4.0 mA cm−2 at 0.6 V vs. RHE. In order to improve the stability of Ag2ZnSnS4 photoanode, TiO2 offering more protection against the photo corrosion was deposited through an atomic layer deposition (ALD) process. IPCE measurements were used to evaluate solar energy utilization efficiencies of AZTS and TiO2/AZTS photoanodes, which showed 25% and 20% IPCE (510–530 nm) in water splitting reaction, respectively. The analysis of gas yield determined that the faradaic efficiency during the H2 evolution process was over 90%. Furthermore, the reasons for the high photoelectrochemical performance of AZTS/Mo-mesh and mechanism of PEC H2 evolution in system are discussed below.

In this study, we synthesized noble metal-free Co3O4 as a cocatalyst for a modified ZnO nanorod photocatalyst to achieve efficient ethylene degradation under light irradiation. The Co3O4-decorated ZnO nanorods demonstrate photocatalytic activity for ethylene oxidation that is better than that of pure ZnO and even better than that of the noble metal-based RuO2-modified ZnO. Furthermore, Co3O4-modified ZnO exhibits good stability in a six-cycle experiment. Measurement results indicate that the Co3O4 nanoparticles can effectively promote the transfer and inhibit the recombination of photogenerated electrons and holes during the photocatalytic reaction. Therefore, the Co3O4-modified ZnO nanorod photocatalyst displays excellent photocatalytic properties for ethylene degradation and can effectively realize the complete mineralization of ethylene molecules.

In this paper, porous microsphere Ag-ZnO photocatalyst was prepared and used in photocatalytic degrading of methane and ethylene at room temperature. The Ag-ZnO photocatalyst showed good stability and high efficiency under the simulated sunlight. Both methane and ethylene can be oxidized into CO2. In the photocatalytic reactions, the decorating of Ag nanoparticles plays key roles in promoting the separation of photo-generated carriers, promoting the oxygen reduction process and realizing the complete mineralization of gas molecules.

To produce hydrogen economically by electrolysis of water, one needs to develop a non-precious-metal catalyst that is as efficient as platinum metal. Here, we prepare such a catalyst by growing a layer of Mo2N over a layer of CeO2 deposited on nickel foam (NF) [hereafter, Mo2N /CeO2@NF] and show that the activity of this self-supported catalyst for hydrogen evolution in 1.0 M KOH is more efficient than that of the Pt/C electrode, achieving a current density of 10 mA/cm2 at a fairly low overpotential of 26 mV. Furthermore, after a long-time electrochemical stability test for 24 h at a fixed current density, the overpotential needed to attain a current density of 10 mA/cm2 is increased only by 6 mV, implying the huge potential of this method to prepare a super HER activity electrode for water splitting.

The removal of nonpolar gaseous ethylene molecules on the plasmonic photocatalyst Ag/AgCl/TiO2 was examined under simulated sunlight irradiation, to find that it has a markedly high activity for the oxidation of ethylene molecules. Systematic experiments, carried out to probe the cause for this observation, indicate that the strong electric field mainly on the Ag nanoparticles (NPs) generated by their surface plasmon resonance (SPR) induces polarization in gaseous ethylene molecules hence enhancing their adsorption on the catalysts and their subsequent photodegradation, and that TiO2 acts as a substrate for dispersing Ag/AgCl nanoparticles to have a larger active surface area. This study provides new ideas towards designing advanced photocatalysts for the degradation of nonpolar gaseous molecules.

In this work, quasi-cube Ag/AgCl plasmonic photocatalyst was synthesized by a simple co-precipitation method and in situ photo-reduction process. The synthesized Ag/AgCl shows high efficiency and good stability in the complete oxidation of nonpolar greenhouse gas methane under the simulated sunlight irradiation. Systematic experiments and finite-difference time-domain (FDTD) simulated calculations were employed to explore the reasons for the appreciable performance improvement, and results showed that the surface plasmonic resonance (SPR) effect of Ag nanoparticles can generate strong electric field which would induce the polarization of methane molecules, hence enhancing the adsorption of methane. This work provides a new idea for exploration of other plasmonic photocatalysts in the field of nonpolar gaseous molecules photo-oxidation.

Developing highly efficient and stable electrocatalyst for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is critical for overall water splitting to solve the shortage of fossil fuel and environment pollution, but it is full of obstacles and challenges. Fe3N@Co4N@CoFe alloy nanoparticles were prepared by using an in situ coupling method. The obtained catalyst showed a satisfactory OER performance in alkaline solution with a low overpotential of 225 mV at 10 mA cm−2 current density and a small Tafel slope of 48 mV/dec. Meanwhile, the HER performance was also improved in alkaline solution after cyclic voltammetry (CV) cycles of OER due to the formation of CoFe oxyhydroxides, which required an overpotential of 135 mV to achieve 10 mA cm−2 current density and a Tafel slope of 109 mV/dec. More importantly, the obtained Fe3N@Co4N@CoFe alloy electrode and Fe3N@Co4N@CoFe alloy-CV electrode (treated through CV cycles of OER) were used as anode and cathode to assemble a two-electrode system for overall water splitting. The constructed system displayed an impressive competency with a voltage of 1.59 V at 10 mA cm−2 current density. The prepared electrocatalysts demonstrated superb long-term stability under 50 mA cm−2 current density for OER, HER and overall water splitting.

Hollow flower-like BiOI photocatalyst (h-BiOI) was obtained via a facile solvothermal method, which consists of ultrathin nanosheets with a thickness of about 2 nm. The structures and morphologies of as-prepared products were characterized by XRD and SEM and the absorption properties were determined by DRS. h-BiOI exhibit a more positive VB band than that of bulk BiOI (b-BiOI), which suggests a much stronger oxidation ability of the former. Therefore, h-BiOI displays completely degradation ability towards RhB under visible light irradiation while b-BiOI only decomposes RhB into segmental fragments under the same conditions. In addition, h-BiOI exhibits significantly higher antibacterial performances than b-BiOI under LED (470 nm) light irradiation. Besides the higher oxidation ability, the excellent photocatalytic activity of h-BiOI may be due to the ultrathin nanosheet, which takes less time for the photogenerated electrons and holes to reach the surface and therefore reduce their recombination.

In this work, a serious of highly efficient and noble metal-free NiS modified MnxCd1-xS nanocomposites were synthesized via a simple direct in suit precipitation process. The as-synthesized products were characterized by XRD, UV–vis DRS, SEM, EDS, TEM, HRTEM, XPS, PL and TRFIA (the time resolved fluorescence spectra). Hydrogen evolution of as-synthesized NiS/MnxCd1-xS composites in the presence of Na2S–Na2SO3 under visible light irradiation (λ ≥ 420 nm) was investigated. The results demonstrated that photocatalytic hydrogen evolution of Mn0.5Cd0.5S was significantly enhanced by loading NiS nanoparticles. As a highly efficient co-catalyst, the optimal NiS loading content was found to be 0.3 wt%, giving a H2 evolution rate of 419.3 μmol/h with an apparent quantum efficiency (QE) of 5.21% (420 nm), which was nearly 18.6 and 3.1 times than that of Mn0.5Cd0.5S and 1.0 wt% Pt/Mn0.5Cd0.5S under the same condition. This work reveals that low cost and earth-abundant NiS can replace noble metals as a highly efficient co-catalyst in hydrogen evolution.

Hydrogen energy with clean, high–energy density, and renewable characteristics has been regarded as an ideal energy to solve the current energy crisis and environmental pollution problems. Water splitting driven by renewable resource–derived electricity and direct use of sunlight based on electrocatalytic and photocatalytic reactions are two promising ways for sustainable hydrogen production. The development and design of efficient electrocatalysts and photocatalysts for hydrogen production is one of the most challenging and demanding missions for today's scientists. In this review, the basic principle and performance evaluation parameters of electrocatalytic and photocatalytic hydrogen production are first introduced, followed by a comprehensive summary of the research progress in electrocatalysts and photocatalysts for hydrogen production from water splitting. Subsequently, special focus is put on the surface and interfacial regulation strategies of electrocatalysts and photocatalysts for improving their H2 production performances from water splitting, including morphology regulation, doping and surface defects, heterojunction construction, and cocatalyst modification. Finally, we also point out that the development of advanced electrocatalysts have the important positive effect for the design of efficient photocatalysts due to the similar nature between the electrocatalysts and cocatalysts in photocatalysis (the active sites that facilitate charge transfer and reduce the reaction energy barrier) during water splitting. We hope that this review article can give some inspirations and guidance for the design of efficient electrocatalytic and photocatalytic water splitting systems.

Electrocatalytic synthesis of hydrogen peroxide (H2O2) via the two-electron oxygen reduction reaction (2e− ORR) is an ideal method for the on-site H2O2 production. Herein, Ni3B is identified as an active, selective, and stable catalyst for ORR to generate H2O2, which exhibits a high selectivity of over 90 % and an onset potential of ∼0.7 V versus the reversible hydrogen electrode (RHE). Furthermore, the mass activity of Ni3B is about 16.5 A g-1 at 0.52 V (RHE), which is comparable to some noble metal alloys. Our experimental results suggest that the high performance of Ni3B originates from the alloying process of Ni and B atoms. The density functional theory calculations reveal that the inner B atoms with high electronegativity decrease the state density of Ni-3d orbital near the Fermi level relative to Ni, which optimizes the binding energy of OOH* and makes Ni3B a highly efficient and stable catalyst for the two-electron ORR.

Plasmonic nanostructures can be used to drive the commercial catalytic reactions under mild conditions by the surface plasmon resonance (SPR). Herein, heterostructural Pd-dotted Ag@Au hexagonal nanoplates (HNPs) are synthesized via an anisotropic growth process, which exhibit 100 % H2 selectivity, highly enhanced catalytic activity (1062 h−1 at 0 °C) for formic acid dehydrogenation by utilizing the light energy. The plasmon-induced mechanism was studied by single-particle photoluminescence (PL) and finite difference time domain (FDTD) simulation. The enhanced interaction between the HCOOH molecules and the catalysts resulting from the surface charge heterogeneity and sharp field-gradient near the Pd-dots region, and bond activation via SPR-enhanced local electromagnetic field are the main contributions for the SPR-induced catalysis. The findings provide a promising approach for the design of hybrid plasmonic photocatalysts to drive harsh chemical conversion at mild conditions.

Cu2O nanoparticles (NPs) enclosed with different crystal facets, namely, c‐Cu2O NPs with {100} facets, o‐Cu2O NPs with {111} facets, and t‐Cu2O NPs with both {111} and {100} facets, are prepared and their electrocatalytic properties for the reduction of CO2 to C2H4 are evaluated. It is shown that the selectivity and activity of the C2H4 production depend strongly on the crystal facets exposed in Cu2O NPs. The selectivities for the C2H4 production increases in the order, c‐Cu2O < o‐Cu2O < t‐Cu2O, (with FEC2H4 = 38%, 45%, and 59%, respectively). This study suggests that Cu2O NPs are more likely responsible for the selectivity and activity for the C2H4 production than the metallic Cu NPs produced on the surface of Cu2O NPs. This work provides a new route for enhancing the selectivity of the electrocatalytic CO2 reduction by crystal facet engineering., The selectivity of CO2 electroreduction to ethylene can be greatly enhanced from Cu2O nanoparticles with both {100} and {111} crystal facets exposed, which is ascribed to the better C–C coupling, ethylene desorption and multielectron transfer kinetics. This work provides a new route for enhancing the selectivity of the electrocatalytic reduction of CO2 to multicarbon products by crystal facet engineering.

In this paper, porous microsphere M-ZnO/CeO2 (M = Ag, Au) plasmonic photocatalyst was prepared through a simple hydrothermal method and in situ photo-deposition. This photocatalyst shows excellent stability and high efficiency in the complete mineralization of nonpolar gaseous molecules (CH4 and C2H4) under the simulated sunlight. The appreciable performance improvements are caused by the formation of heterojunctions and oxygen vacancy defects, the surface plasmon resonance (SPR) of noble metal nanoparticles as well as the 3D porous microsphere structures. Especially in this work, we systematically studied the effect of concentration changes of oxygen vacancy defects on photocatalytic performance by XPS, EPR and Raman characterization. Furthermore, a possible mechanism of photo-oxidation reaction in plasmonic photocatalyst system is discussed below. This study provides new inspiration for designing other plasmonic photocatalysts to remove nonpolar gaseous molecules.