Nanoporous bismuth vanadate is modified simultaneously via tungsten doping and graphene surface modification for use as an efficient photoanode. The modified films were prepared on a FTO substrate by a drop-cast method followed by photoreduction of graphene oxide. SEM, XRD, Raman and XPS characterization was conducted to confirm the incorporation of tungsten and reduced graphene oxide (RGO), and to look into their influences on the structure and performance of BiVO₄. Electrochemical impedance spectroscopy analysis clearly revealed enhanced carrier density and improved electronic conductivity, which are beneficial for the enhancement of PEC performance in comparison to either individually doped or RGO modified BiVO₄. Our results indicated that the enhanced PEC performance can be attributed to the synergistic effect of bulk doping and surface modification that facilitates electron and hole transport and transfer in the bulk and at the semiconductor–electrolyte interface.

Metal-nitrides-based electrocatalysts for efficient oxygen-evolution have been extensively studied as one of the most promising candidates to fulfil the demand for future energy-conversion and storage. Herein, a series of Ni_xCo_1−xO- and Ni_xCo_1−xN-based nanostructures on nickel foams were reported to show excellent activities for oxygen-evolution reaction. The catalysts were prepared and modulated rationally via a facile-hydrothermal method, followed by high-temperature calcination under air or nitrogen atmosphere. The optimal bimetallic-nitride catalyst Ni_0.3Co_0.7N shows a small overpotential of 268 mV at 20 mA cm⁻², and a Tafel slope of 66 mV dec⁻¹ with good stability. The enhanced OER-performance is ascribed to the synergetic effect of the unique morphology and the intrinsic catalytic property of the nanostructure after nitridation.

A novel hybrid structure of bimetallic dicyanamide decorated BiVO₄ is developed via a simple method to accelerate interfacial water oxidation kinetics. Two types of bimetallic dicyanamides, CoNi(dca)₂ and CoFe(dca)₂, are coated on BiVO₄ photoanodes and are found to exhibit far more enhanced PEC performance than Co(dca)₂ or Ni(dca)₂ as cocatalysts. The successful deposition of metal dicyanamides on BiVO₄ photoanodes is confirmed by physical characterizations including X-ray photoelectron spectroscopy (XPS). The optimized Co_0.9Ni_0.1(dca)₂/BiVO₄ photoanode exhibits the highest photocurrent density of 2.58 mA/cm² at 1.23 V vs. RHE under 100 mW/cm² AM 1.5 G irradiation, which is 2.5 times that of bare BiVO₄. The substantial enhancement of PEC performance can be ascribed to the advantageous interfacial charge transfer and improved charge injection efficiencies. This work presents a feasible strategy using different types of bimetallic dicyanamides to design a modified BiVO₄-based photoanode system for enhanced water oxidation efficiency.