Surface Engineering of 3D Gas Diffusion Electrodes for High‐Performance H ₂ Production with Nonprecious Metal Catalysts

Journal Article · Tue Sep 17 00:00:00 EDT 2019 · Advanced Energy Materials

DOI:https://doi.org/10.1002/aenm.201901824· OSTI ID:1562331

Sanchez, Joel ^[1]; Hellstern, Thomas R. ^[2]; King, Laurie A. ^[1]; Jaramillo, Thomas F. ^[3]

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1. Department of Chemical Engineering Stanford CA 94035 USA, SUNCAT Center for Interface Science and Catalysis Stanford University Stanford CA 94035 USA
2. Department of Chemical Engineering Stanford CA 94035 USA
3. Department of Chemical Engineering Stanford CA 94035 USA, SUNCAT Center for Interface Science and Catalysis Stanford University Stanford CA 94035 USA, SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA

Abstract

In this work, a methodology is demonstrated to engineer gas diffusion electrodes for nonprecious metal catalysts. Highly active transition metal phosphides are prepared on carbon‐based gas diffusion electrodes with low catalyst loadings by modifying the O/C ratio at the surface of the electrode. These nonprecious metal catalysts yield extraordinary performance as measured by low overpotentials (51 mV at −10 mA cm ⁻² ), unprecedented mass activities (>800 A g ⁻¹ at 100 mV overpotential), high turnover frequencies (6.96 H ₂ s ⁻¹ at 100 mV overpotential), and high durability for a precious metal‐free catalyst in acidic media. It is found that a high O/C ratio induces a more hydrophilic surface directly impacting the morphology of the CoP catalyst. The improved hydrophilicity, stemming from introduced oxyl groups on the carbon electrode, creates an electrode surface that yields a well‐distributed growth of cobalt electrodeposits and thus a well‐dispersed catalyst layer with high surface area upon phosphidation. This report demonstrates the high‐performance achievable by CoP at low loadings which facilitates further cost reduction, an important part of enabling the large‐scale commercialization of non‐platinum group metal catalysts. The fabrication strategies described herein offer a pathway to lower catalyst loading while achieving high efficiency and promising stability on a 3D electrode.

• Sponsoring Organization: USDOE
• Grant/Contract Number: AC02-76SF00515
• OSTI ID: 1562331
• Journal Information: Advanced Energy Materials, Journal Name: Advanced Energy Materials Journal Issue: 40 Vol. 9; ISSN 1614-6832
• Publisher: Wiley Blackwell (John Wiley & Sons)
• Country of Publication: Germany
• Language: English