Rapid Synthesis of Phase-Engineered Tungsten Carbide Electrocatalysts via Flash Joule Heating for High-Current-Density Hydrogen Evolution

Fabricating durable and high-performance electrocatalysts operating at high current densities for industrial acidic hydrogen evolution remains a daunting challenge. Tailoring the phase composition of electrocatalysts is a promising strategy to harness synergistic effects and improve charge transfer, thereby optimizing their performance. This work presents a fast, green method based on flash joule heating (FJH) to synthesize phase-engineered tungsten carbide electrocatalysts for the acidic hydrogen evolution reaction (HER) at high current densities. Tungsten carbide electrodes with varying FJH treatment durations (3, 10, 30, and 60 seconds) are fabricated to fine-tune the mixture of tungsten monocarbide (WC) and tungsten semicarbide (W2C) phases. Results show that samples with a 30-second treatment (TC-3) exhibit an optimal balance between these phases, leading to a low overpotential of 387 mV at a high current density of 4 A/cm2. Notably, the TC-3 electrocatalysts remain stable for over 6 days at 4 A/cm2 due to their controlled phases and excellent corrosion-resistant properties. This work highlights a new method to fabricate cost-effective, high-performance tungsten carbide electrocatalysts with well-controlled phase compositions.