Surface Engineering of 3D Gas Diffusion Electrodes for High‐Performance H2 Production with Nonprecious Metal Catalysts. Issue 40 (17th September 2019)

• Record Type: Journal Article
• Authors: Sanchez, Joel; Hellstern, Thomas R.; King, Laurie A.; Jaramillo, Thomas F.
• Is Part Of: Advanced energy materials. Volume 9:Issue 40(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-09-17
• Subjects: cobalt phosphide -- electrode engineering -- hydrogen evolution reaction -- hydrophilicity -- low‐loading; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201901824
• Languages: English
• ISSNs: 1614-6832

Abstract

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 H2 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. Abstract : Highly active transition metal phosphide hydrogen evolution catalysts with low overpotentials, unprecedented mass activities, high turnover frequencies, and promising durability are prepared by modifying the wetting properties of the underlying electrode. The origin of the improved performance is linked to an improved catalyst dispersion and morphology enabling high surface area CoP formulations at low loadings.