Boosting oxygen reduction performances in Pd-based metallenes by co-confining interstitial H and p-block single atoms

Abstract

The efficiency of the oxygen reduction reaction (ORR) is limited by the scaling relationship in the conventional oxygen associative pathway. To break such limitations, we present an approach to effectively activate the oxygen dissociative pathway through co-confining single p-block (In, Sn, Pb) atoms and interstitial H atoms within Pd metallenes, leading to good ORR performance. PdPbH_x metallenes exhibit a high mass activity of 1.36 A mg⁻¹ at 0.95 V (vs. RHE), which is 46.9 times higher than that of the benchmark Pt/C. The minimal performance decay after 50,000 potential cycles confirms a good stability. In situ vibrational spectroscopy investigations and theoretical calculations highlight that interstitial H atoms facilitate the direct dissociation of O₂ while single Pb atoms enhance O₂ adsorption strength. The electroactive PdPbH_x metallenes is attributed to the up-shifted Pd-4d orbitals induced by H and Pb atoms. This research supplies critical inspiration for developing highly efficient ORR electrocatalysts.