Effects of pH on the Hierarchical Structures and Photocatalytic Performance of BiVO₄ Powders Prepared via the Microwave Hydrothermal Method

BiVO₄ powders with hierarchical structures were prepared by the microwave hydrothermal method at different pHs, using Bi­(NO₃)₃·5H₂O and NH₄VO₃ as raw materials. The results show that, when the pH value of the precursor is 0.59, the as-prepared powders are monoclinic BiVO₄ crystals with octahedron and decahedron morphologies. Spherical and polyhedral BiVO₄ with particle sizes in the range of 2–4 μm can be prepared under the strong acid condition (pH = 0.70–1.21) and possess a mixed crystal consisting of tetragonal and monoclinic phases, whereas rodlike and dendritic BiVO₄ with a pure monoclinic phase can be obtained within a very wide pH range (pH = 4.26–9.76). The phase transformation from tetragonal phase to monoclinic phase occurs at pH 3.65. At pH >9.76, the powders are the nonstoichiometric crystals between the mixed-phase BiVO₄ and non-BiVO₄. The photocatalytic efficiencies were evaluated by the degradation of Rhodamine B (RhB) under UV and simulated sunlight irradiation. The corresponding relationship among pH values of the precursor, crystalline phase, morphology, and photocatalytic performance of the powders was also discussed

Heterostructured Ru/Ni(OH)₂ Nanomaterials as Multifunctional Electrocatalysts for Selective Reforming of Ethanol

The electrochemical reforming of ethanol into hydrogen and hydrocarbons can reduce the electric potential energy barrier of hydrogen production from electrochemical water splitting, obtaining high value-added anode products. In this work, Ru/Ni(OH)2 heterostructured nanomaterials were synthesized successfully by an in situ reduction strategy with remarkable multifunctional catalytic properties. In the hydrogen evolution reaction, Ru/Ni(OH)2 exhibits a smaller overpotential of 31 mV to obtain a current density of 10 mA/cm2, which is better than that of commercial Pt/C. Notably, such heterostructured Ru/Ni(OH)2 nanomaterials also perform an outstanding catalytic selectivity toward an acetaldehyde product in the oxidation of ethanol. DFT calculations reveal that abundant Ru(0)-Ni(II) heterostructured sites are the key factor for the excellent performances. As a result, an ethanol-selective reforming electrolyzer driven by a 2 V solar cell is constructed to produce hydrogen and acetaldehyde in the cathodic and anodic part, respectively, via using Ru/Ni(OH)2 heterostructured catalysts. This work provides a forward-looking technical guidance for the design of novel energy conversion systems

Heterostructured Ru/Ni(OH)₂ Nanomaterials as Multifunctional Electrocatalysts for Selective Reforming of Ethanol

The electrochemical reforming of ethanol into hydrogen and hydrocarbons can reduce the electric potential energy barrier of hydrogen production from electrochemical water splitting, obtaining high value-added anode products. In this work, Ru/Ni(OH)2 heterostructured nanomaterials were synthesized successfully by an in situ reduction strategy with remarkable multifunctional catalytic properties. In the hydrogen evolution reaction, Ru/Ni(OH)2 exhibits a smaller overpotential of 31 mV to obtain a current density of 10 mA/cm2, which is better than that of commercial Pt/C. Notably, such heterostructured Ru/Ni(OH)2 nanomaterials also perform an outstanding catalytic selectivity toward an acetaldehyde product in the oxidation of ethanol. DFT calculations reveal that abundant Ru(0)-Ni(II) heterostructured sites are the key factor for the excellent performances. As a result, an ethanol-selective reforming electrolyzer driven by a 2 V solar cell is constructed to produce hydrogen and acetaldehyde in the cathodic and anodic part, respectively, via using Ru/Ni(OH)2 heterostructured catalysts. This work provides a forward-looking technical guidance for the design of novel energy conversion systems

Heterostructured Ru/Ni(OH)₂ Nanomaterials as Multifunctional Electrocatalysts for Selective Reforming of Ethanol

The electrochemical reforming of ethanol into hydrogen and hydrocarbons can reduce the electric potential energy barrier of hydrogen production from electrochemical water splitting, obtaining high value-added anode products. In this work, Ru/Ni(OH)2 heterostructured nanomaterials were synthesized successfully by an in situ reduction strategy with remarkable multifunctional catalytic properties. In the hydrogen evolution reaction, Ru/Ni(OH)2 exhibits a smaller overpotential of 31 mV to obtain a current density of 10 mA/cm2, which is better than that of commercial Pt/C. Notably, such heterostructured Ru/Ni(OH)2 nanomaterials also perform an outstanding catalytic selectivity toward an acetaldehyde product in the oxidation of ethanol. DFT calculations reveal that abundant Ru(0)-Ni(II) heterostructured sites are the key factor for the excellent performances. As a result, an ethanol-selective reforming electrolyzer driven by a 2 V solar cell is constructed to produce hydrogen and acetaldehyde in the cathodic and anodic part, respectively, via using Ru/Ni(OH)2 heterostructured catalysts. This work provides a forward-looking technical guidance for the design of novel energy conversion systems