Carbon-coated metal materials derived from metal-regulated coordination polymers and γ-polyglutamic acid for efficient removal of environmental pollutants

Abstract

Since organic dye pollution has a detrimental impact on the environment, eliminating and separating them ought to be one of the best ways to address the problem. Two metal–organic coordination polymers (MOCPs), Cu-CP and Ni-CP, were successfully synthesized under hydrothermal conditions and utilized to degrade organic dyes in aqueous solution by photocatalysis. MOCPs were employed as precursors for carbon-coated metal materials (Cu@C and Ni@C) and vanillin-coated metal materials (Cu@γ-PGA and Ni@γ-PGA) by direct pyrolysis and doping pyrolysis, respectively. Doping γ-polyglutamic acid into intrinsic MOCPs significantly improved photocatalytic activity. Ni@γ-PGA demonstrated effective photocatalytic degradation of five organic dyes, particularly MB, with a 99.28 % efficiency. Experiments with free radical capture indicated that ·O₂⁻ was the most important factor in photocatalysis. Additionally, tests using photoluminescence (PL), photoelectrochemical (PEC) analysis, X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflection spectrum (DRS) demonstrated that Ni@γ-PGA can improve the rapid migration and separation of photo-generated carriers, increase photocatalytic activity, and effectively delay the recombination of photo-generated charges. A new idea for the creation of effective and recyclable semiconductor photocatalytic materials was presented in this study.