Stacked nano rods of cobalt and nickel based metal organic frame work of 2–amino benzene dicarboxylic acid for photocatalytic hydrogen generation

Abstract

Stacked nanorods of cobalt and nickel based hetero bimetallic organic frameworks (MOFs) of 2–amino benzene dicarboxylic acid are developed as photocatalyst for hydrogen evolution reaction. The ratio of metals in the catalyst is tuned to achieve a narrow band gap, and the MOF with optimized Ni to Co ratio of 1: 0.5 (1Ni0.5Co@NH2BDC) exhibited the lowest band gap (2.2 eV) and electron–hole recombination rate. The catalyst exhibits enhanced photocatalytic activity for hydrogen evolution reaction due to the absorption of photons by 2–amino benzene dicarboxylic acid and excitation of electrons from HOMO to LUMO of the organic linker. The excited electrons relay to the cluster of the framework and reduce the protons gather around the cluster to hydrogen. The holes in the HOMO state are occupied by the electrons from the sacrificial agents and it supports the photocatalytic hydrogen evolution by avoiding electron–hole recombination. The stability of MOF catalyst in water splitting medium even with sacrificial agents confirms its competency with the state–of–the–art photocatalytic materials.