Snowflake Like Cu-BDC-NH2/Cu58S32 Nanocomposite for Photocatalytic H2 Evolution and O2 Reduction

Abstract

This work presents the synthesis of unique binary Cu-BDC-NH2/Cu58S32 (CSM) heterostructure which is synthesized via one-pot solvothermal route. The nonstoichiometric pure roxbyite (Cu58S32) phase was synthesized and evolution of distinct morphologies like nanoplate (np) and snowflake (sf) was achieved by varying the sulfur sources. To construct the heterostructure, Cu58S32 (CS) is used as host matrix as well as copper source to fabricate CuBDC-NH2 MOF (CM) nano plate over it. A substantial interfacial contact area of a n–p heterojunction was formed by the controlled development of CM nanoplates over the wellcrystalline and radially symmetric hexagonal dendritic structure of CS. Comprehensive characterization of CSM nanocomposite revealed that the optical, electrical and active surface area is improved due to the construction of CSM hetero structure compared to the pristine semiconducting CS and CM, results synergistic charge separation and mobilization. Three different forms of coordinated metal sites, including monomeric Cu(II) with a distorted ligand environment and Cu(II) dimers with a paddle wheel structure, were found in the surfacealigned ultrathin CM nanosheets that anchored over CS matrix. The synthesized materials are employed for photocatalytic H2 evolution reaction (PHER) and O2 reduction (POR) under simulated solar light irradiation. The morphological investigation unveiled that snowflake like structure shows superior physio-chemical activities than nano-plate like structure. Thus, the optimized CSM(sf)-7 nanocomposite showed superior photocatalytic activity with S-Schem mechanism towards H2 production (9343 μmolg –1 h –1 ) and O2 reduction (2339 μmolg –1 h –1 ) which is 14-20 fold higher than the constituent pristine semiconductors [1].