Amino-Acid-Functionalized Metal–Organic Frameworks as Excellent Precursors toward Bifunctional Metal-Free Electrocatalysts

Abstract

Metal–organic frameworks (MOFs) are promising precursors for synthesizing functional carbon materials, and their atomic-scale designs have recently been studied for improving their performance. Herein, we synthesized an alanine-decorated MOF-5 via a solvothermal method using a mixture of dimethylformamide and water as the solvent. Experimental and computational investigations revealed that alanine residues were located in the micropores of MOF-5 due to interactions between the MOF Zn clusters and the carboxylic acid groups of the alanine moieties. In addition, the alanine-decorated MOF-5 was carbonized at 1100 °C for application as an electrocatalyst. It was found that the resulting N-doped carbonized sample exhibited excellent catalytic activities in the oxygen reduction and hydrogen evolution reactions and afforded superior results to those reported for other metal-free carbon catalysts. This high activity originated from the single nitrogen configuration (pyrrolic N) in the hierarchical pores. This article presents a facile strategy for the syntheses of both functionalized MOFs and N-doped carbon materials.