Selective Hydrogen Oxidation Catalyst for PEM Fuel Cells: Tungsten Cluster-Tuned Platinum Single Atoms

The selective hydrogen oxidation reaction (HOR) electrocatalyst is crucial for enhancing the performance of proton-exchange membrane fuel cells (PEMFCs) against degradation caused by reverse currents. In this study, a catalyst comprising platinum single atoms (Pt₁) finely tuned by tungsten nanoclusters (W_NC) on an accordion-like nitrogen-doped carbon support (ANC) is presented. The tungsten nanoclusters, derived from phosphotungstic acid, are embedded within the carbon support, while the Pt single atoms are uniformly dispersed on its surface. Experimental results and theoretical calculations reveal that the W_NC effectively reduce the hydrogen adsorption strength on Pt₁ to an optimal level, thereby facilitating HOR catalysis. Notably, this adjustment also weakens oxygen adsorption, rendering Pt₁ less effective for catalyzing the oxygen reduction reaction. Consequently, the catalyst Pt₁/W_NC-ANC exhibits high resistance to degradation from reverse currents when oxygen leaks into the anode. Meanwhile, it demonstrates an ultralow HOR overpotential with an outstanding mass activity, 13 times greater than commercial Pt/C. This work provides a highly active and selective low-Pt HOR catalyst, paving the way for the development of cost-effective, long-lasting, and robust PEMFCs.