Optimizing interfacial electronic coupling with metal oxide to activate inert polyaniline for superior electrocatalytic hydrogen generation

Tuning and optimization of electronic structures and related reaction energetics are critical toward the rational design of efficient electrocatalysts. Herein, experimental and theoretical calculation demonstrate the originally inert N site within polyaniline (PANI) can be activated for hydrogen evolution by proper d-π interfacial electronic coupling with metal oxide. As a result, the as-synthesized WO₃ assemblies@PANI via a facile redox-induced assembly and in situ polymerization, exhibits the electrocatalytic production of hydrogen better than other control samples including W₁₈O₄₉@PANI and most of the reported nobel-metal-free electrocatalysts, with low overpotential of 74 mV at 10 mA·cm⁻² and small Tafel slope of 46 mV·dec⁻¹ in 0.5M H₂SO₄ (comparable to commercial Pt/C). The general efficacy of this methodology is also validated by extension to other metal oxides such as MoO₃ with similar improvements.