Biochar-based nanocomposites are recognized as promising catalysts for peroxymonosulfate (PMS) activation due to their cost-effectiveness, large surface area, and desirable activity. However, their conventional preparation involves laborious and energy-consuming high-temperature pyrolysis. In this study, we introduce an efficient approach to synthesize FeCu@BC nanocomposites using iron and copper chlorides with green tea via a mechanochemical method. Characterization results show that copper incorporation enhances the defect degree of biochar, increasing oxygen vacancies in FeCu@BC. Remarkably, FeCu@BC exhibits an outstanding efficiency of 92.24% in degrading TC, achieving more than 85% TC removal even under challenging conditions with varying pH levels and competing ions, making it a promising catalyst for practical applications. Through detailed investigations, we identify O2 center dot  and 1O2 as the primary active species responsible for TC degradation, supported by quenching and EPR tests. Furthermore, copper doping significantly improves electron transfer between FeCu@BC and PMS, promoting PMS activation during degradation. XPS analysis provides insights into the transformation of doped copper species, acting as potential active sites that facilitate PMS decomposition to generate O2 center dot  and 1O2. With significant advantages in cost-effectiveness and avoidance of energy-intensive pyrolysis, the mechanochemically synthesized FeCu@BC nanocomposites hold great promise for wide application in efficient wastewater treatment and environmental remediation.
