Optimizing Oxygen and Intermediate HOO* Adsorption of Cu-Pd Alloy Cocatalyst for Boosting Photocatalytic H2O2 Production of BiVO4

The modification of Pd cocatalysts is considered to be an effective strategy to improve H2O2 production of photocatalysts because it can accelerate the reaction rate of O-2 reduction. However, the strong adsorption between O-2 molecules and Pd atoms is not conducive to the formation of intermediate HOO* and leads to the further reduction of H2O2 to H2O, thus limiting the improvement of H2O2 production. To solve the issue, in this work, Cu-Pd alloy cocatalysts are selectively modified on the electron-rich facets of BiVO4 via facile photoinduced deposition and subsequent galvanic displacement. DFT calculations indicate that the incorporation of Cu atoms to Pd atoms weakens the oxygen adsorption energy and HOO* binding energy on Pd atom surfaces, thus increasing the activity and selectivity of O-2 reduction to H2O2. Further experimental results show that the optimized Cu-Pd/BiVO4 (5:1) photocatalyst exhibits markedly boosted activity for H2O2 production (2189 mu mol L-1), which is 3.2-fold higher than that of BiVO4 with modification of 0.3 wt% Pd cocatalyst (675 mu mol L-1). Additionally, the incorporation of metal Cu enables the economic utilization of Pd atoms and reduces the expense of the Pd cocatalyst.

Automated summary

Modifying Pd cocatalysts is an effective strategy to improve H2O2 production of photocatalysts, however, it can lead to the further reduction of H2O2. In this study, Cu-Pd alloy cocatalysts were selectively modified on the electron-rich facets of BiVO4 to weaken the adsorption energy of oxygen and increase the activity and selectivity of O-2 reduction to H2O2. The optimized Cu-Pd/BiVO4 photocatalyst demonstrated significantly higher H2O2 production compared to BiVO4 with Pd cocatalyst.