Tungsten carbide nanowalls as electrocatalyst for hydrogen evolution reaction: New approach to durability issue

- We demonstrate the drastic enhancement in the durability of the tungsten carbide electrocatalyst by microstructural change.
- No further oxide passivation was observed upto 10,000 cycling after removal of initial oxide passivation layer on the WC nanowall electrocatalyst.
- The excellent durability was attributed to its crystalline perfection and the atomically smooth surface.

We report a new approach to the durability issue in tungsten carbide electrocatalyst for hydrogen evolution reaction (HER), in a form radically differing from that of the conventional nanoparticle approach: the WC nanowalls, bottom-up grown by a plasma-assisted deposition on Si wafer. The pristine nanowall was highly crystalline and its surface was smooth in atomic scale, which enabled a superior durability in HER environment: no oxidation occurred at prolonged cycling (10,000 cycles) in the HER environment, even without additional functionalization or modification. The electrochemical activity, as presented by Tafel slope and turnover frequency (TOF), was as excellent as those of the best data in the literature.

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