Tailoring the Reaction Pathway of Glycerol Selective Oxidation by Constructing a Built-In Electric Field in Mott–Schottky Heterostructure Electrocatalyst Ni(OH)2–In

Abstract

Replacing the anodic oxygen evolution reaction with electro-oxidation of glycerol for hydrogen energy not only reduces energy consumption but also obtains high-value chemicals. However, this system still faces bottlenecks of limited Faradaic efficiency, low selectivity, and an unclear reaction pathway. Herein, the Mott–Schottky Ni(OH)₂–In heterostructure was prepared for selective glycerol electro-oxidation (GOR). A series of experiments and theoretical calculations validated the charge shuttling through a heterointerface and the formation of the built-in electric field (BIEF) structure. As expected, the Ni(OH)₂–In delivered a low potential of 1.22 V vs RHE at 10 mA cm^–2. The Faradaic efficiency and selectivity for formate are up to 93% and 95%, respectively, together with long-term stability for the 20 cycles. The excellent performance can be attributed to the changed reaction pathway of producing the formate, reduced reaction energy barrier of the rate-determining step (RDS), and a more rapid GOR kinetics which arise from the robust BIEF. This work indicates that via constructing BIEF in the Mott–Schottky heterostructure, the electrocatalytic glycerol oxidation can be promoted.