CeO2-regulated NiCoOOH formed via electrocatalytic self-reconstruction of NiCoCe-MOFs for efficient electro-oxidation of 5-hydroxymethylfurfural

Abstract

CeO2-regulated NiCo oxyhydroxide nanosheet electrocatalyst (i.e., CeO2/NiCoOOH) was fabricated by electrocatalytic self-reconstruction of NiCoCe-MOFs. The in-situ self-reconstruction exposes additional active sites on the NiCoOOH surface, leading to enhanced intrinsic electrocatalytic activity. CeO2/NiCoOOH has better performance on both OER and HMFOR than the original MOFs. CeO2 acts as an 'electron trap', modulating the electron density of Ni and Co, refining the electronic configuration of NiCoOOH, and expediting the electron transfer kinetics. Therefore, the self-reconstructed CeO2/NiCoOOH showed higher current density (92.7 mA/cm2) than NiCoOOH (49.8 mA/cm2) in electrocatalytic oxidation at 1.5 VRHE (1.0 M KOH+50 mM HMF). After 5 cycles of testing, CeO2/NiCoOOH still has excellent HMF conversion (95.87%), Faraday efficiency (95.22%) and FDCA yield (99.26%). Theoretical calculations revealed that the introduction of CeO2 significantly lowers the energy barrier for the critical step at the Co site, optimizes the adsorption of HMF, thereby facilitating the electrocatalytic HMFOR process.