Operation-Induced BiVO4 Surface Reconstruction Modulates Photoelectrochemical Glycerol Photooxidation Stability and Activity

Résumé fourni par la source

Operation-induced surface reconstruction of photoelectrodes is poorly understood and underexplored as a path to control photoelectrochemical stability. Here, we show how adaptive junctions form in association with the surface reconstruction of bismuth vanadate during glycerol oxidation and how these surfaces have electrolyte-dependent kinetics and effects on durability. Preferential vanadium dissolution in both acidic and alkaline media forms a bismuth-rich layer, for which opposing catalytic roles with respect to pH are found. In situ measurements through a dual-working-electrode platform quantify the changes in photovoltage and charge-transfer resistance derived from adaptive junction formation during glycerol oxidation, while also enabling quantitative separation of the driving forces for charge separation and interfacial catalysis. The reconstructed surface in acidic media improves hole transfer kinetics, functions as a glycerol oxidation catalyst, and imparts photostability. Surface reconstruction in alkaline media exhibits the opposite behavior, impeding hole injection. The resulting instability is mitigated through in situ surface activation by adding trace Ni 2+ ions to the electrolyte without cocatalyst predeposition. This study thus shows the significance of surface reconstruction for the design of durable photoelectrodes for applications using anodic organic electro-oxidation.

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