Nanogalvanic cell catalysts: bridging electrochemical and thermal catalysis

ABSTRACT Selective nitroarene hydrogenation to anilines faces an intractable activity-selectivity trade-off: conventional Horiuti-Polanyi (H-P) catalysis triggers over-hydrogenation of coexisting unsaturated groups via free H* species. Herein, we report Pt@C/TiO2 as a nanogalvanic cell catalyst (NGC) that bridges electrochemical and thermal catalysis by integrating concerted proton–electron transfer (CPET) into heterogeneous catalysis. In Pt@C/TiO2, Pt nanoparticles wrapped by an ultrathin carbon shell catalyze H2 oxidation, whereas TiO2 hosts nitro reduction. Protons migrate through solvent hydrogen-bond networks and electrons transfer through the conductive TiO2 support, enabling a CPET-like reduction that largely bypasses the H-P route without direct substrate-Pt contact. Electrochemical coupling analyses corroborate galvanic-cell operation. Pt@C/TiO2 affords near-quantitative conversion and > 97% selectivity to 4-aminostyrene from 4-nitrostyrene, while the carbon shell blocks CO/sulfur access to Pt, delivering exceptional poisoning tolerance and stability. This NGC paradigm offers a general strategy for site-separated redox catalysis combining electrocatalytic selectivity with thermal-process simplicity.