Quantifying the contribution of lanthanum single atoms in photocatalytic Fenton-like processes with a rigorous benchmarking protocol

Abstract

Single-atom catalysts (SACs) are increasingly of interest for Fenton-like processes for water treatment due to maximized metal utilization. However, their feasibility has not been conclusively demonstrated, partly due to inconsistent preparation and benchmarking. Here, we verify the catalytic activity of lanthanum single atoms for pollutant degradation by a rigorous benchmarking protocol that considers the contributions of adsorption, catalytic activity of supports, and leached ions. The reaction rate constant increases linearly with lanthanum loading up to 9 wt %, illustrating the viability of synchronously realizing high specific activity and maximized atom utilization. In addition, we show that the synergetic activation of peroxymonosulfate (PMS) and oxygen to produce multiple reactive oxygen species (ROS) is responsible for the catalytic performance, revealing the previously ignored contributions of air in catalytic systems. We anticipate that this protocol will aid in the development of SACs to realize their full prospects.