Boosted photocatalytic performance on molecule/semiconductor hybrid materials: conversion of sunlight energy into hydrogen fuel

Abstract

Molecular metal–organic complexes and conventional photocatalysts are the “silver bullets” for energy transformation from solar sources. However, use of single metal–organic complexes and semiconductors carries a unique set of disadvantages, such as sluggish separation/transfer of electron–hole pairs. However, “bridges” can be built between a molecule and semiconductor to overcome this problem. Here, excellent photocatalytic performance for a molecule/semiconductor hybrid material g-C₃N₄/Co(L)₂(H₂O)₂ (HL = quinoline-2,3-dicarboxylic acid) was displayed. The g-C₃N₄/1.0 wt%Co(L)₂(H₂O)₂ hybrid material exhibited a highest photocatalytic H₂ generation of 224.63 μmol g⁻¹ h⁻¹. Rapid photogeneration was observed using g-C₃N₄ and Co(L)₂(H₂O)₂ due to formation of a weak amide linkage, which facilitated the overall reaction kinetics. Meanwhile, according to previous studies, two H₂O ligand molecules coordinated with Co to afford two active sites in the axial position. Our research provides an important strategy for rational design of inexpensive and high-efficiency novel photocatalytic materials based on a covalent grafted molecule/semiconductor hybrid material.