2D Conjugated Metal–Organic Frameworks as Electrocatalysts for Boosting Glycerol Upgrading Coupled with Hydrogen Production

The valorisation of glycerol using renewable electricity is recognised as an effective and attractive approach for producing high-value compounds from biomass byproducts. 2D conjugated metal-organic frameworks (2D c-MOFs) have emerged as promising electrocatalysts due to their tunable structures, high electronic conductivity, and efficient utilisation of well-defined active centres. In this study, we report the first systematic investigation of 2D c-MOFs containing Ni-X₄ (X = O or N) moieties for the glycerol oxidation reaction (GOR), examining key factors influencing both electrocatalytic activity and selectivity. In situ ¹³C electrochemical nuclear magnetic resonance and Raman spectroscopies provide insights into the GOR mechanism and confirm that Ni-O₄ sites are the primary active centres. Theoretical calculations further reveal that [Ni₃(HHTQ)₂]_n (HHTQ = 2,3,7,8,12,13-hexahydroxytricycloquinazoline) exhibits superior GOR activity due to strong adsorption of reaction intermediates and weak interlayer interactions. This work highlights the potential of 2D c-MOFs as highly efficient GOR catalysts, paving the way for the rational design of advanced electrocatalysts and contributing to the development of sustainable energy conversion and storage technologies.