Facile construction of a BiVO₄/CoV-LDHs/Ag photoanode for enhanced photo-electrocatalytic glycerol oxidation and hydrogen evolution

Replacing water oxidation by the thermodynamically more favorable glycerol oxidation reaction in a photoelectrochemical (PEC) cell is highly desirable, which can not only improve the energy efficiency of hydrogen evolution, but also produce value-added chemicals, given that glycerol is easily accessible as a major byproduct from the biodiesel industry. Herein, a BiVO4/CoV-LDHs/Ag photoanode has been fabricated via a simple electrodeposition and redox strategy, which exhibits excellent PEC activity toward glycerol oxidation. A high photocurrent density of 7.15 mA cm(-2) can be achieved at 1.23 V vs. reversible hydrogen electrode, in 0.5 M Na(2)SO(4 )solution with 0.1 M glycerol under AM 1.5G illumination, which is 2.7 times that of the pristine BiVO4 photoanode. The significantly enhanced PEC performance can be attributed to the narrowed optical band gap, and improved charge separation and injection efficiencies after surface deposition of CoV-LDHs/Ag on the BiVO4 photoanode. As a result, greatly improved hydrogen production efficiency has been achieved by coupling the photo-electrochemical glycerol oxidation on the BiVO4/CoV-LDHs/Ag photoanode, with the evolved hydrogen gas (123.5 mmol m(-2) h(-1)) nearly double that when using the pristine BiVO4 photoanode.