Fabrication of an amorphous metal oxide/p-BiVO photocathode: understanding the role of entropy for reducing nitrate to ammonia

The controllable design of chemical microenvironment with the expected thermodynamics and kinetics for boosting catalytic activity and selectivity presents a challenge. Herein, an amorphous metal oxide (A-M x O y ) was employed to understand the polymetallic association of the effect of entropy, revealing the interplay between entropy and the NO 3 − reduction reaction (NITRR) in a photoelectrochemical (PEC) system. Based on ultrafast transient absorption spectroscopy, the signal recovery of an optimal heterostructure (CoFeMnO/BiVO 4 ) was 9.1 ps, confirming that amorphous CoFeMnO effectively promotes the kinetic factor of electrons. Thus, the NH 3 yield rate of the optimal heterostructure (CoFeMnO/BiVO 4 ) is up to 17.82 μg h −1 cm −2 (at −0.1 V vs. RHE), which is almost twice that of p-BiVO 4 . Furthermore, isotope 1 H nuclear magnetic resonance spectroscopy was used to further demonstrate the exactitude of the NH 3 evolutionary process, using 15 NO 3 − as the N resource. Therefore, desirable entropy regulation and NH 3 production make the herein A-M x O y /BiVO 4 heterostructure a promising NITRR catalyst for use in a future solar conversion system. Entropy regulation makes an amorphous metal oxide/p-BiVO 4 heterostructure a desirable catalyst for the NO 3 − reduction reaction in a photoelectrochemical system.