Structure-Activity Correlations of Phosphorous-Containing Cobalt Electrocatalysts: Insights into the Local Order by Pair Distribution Function Analysis

37 Pages Posted: 21 Mar 2023

See all articles by Álvaro Vílchez-Cózar

Álvaro Vílchez-Cózar

affiliation not provided to SSRN

Rosario M.P. Colodrero

affiliation not provided to SSRN

Montse Bazaga-García

affiliation not provided to SSRN

David Marrero-López

affiliation not provided to SSRN

Sayed M. El-refaei

affiliation not provided to SSRN

Patricia A. Russo

Humboldt University of Berlin

Nicola Pinna

Humboldt University of Berlin

Pascual Olivera-Pastor

affiliation not provided to SSRN

Aurelio Cabeza Díaz

affiliation not provided to SSRN

Abstract

Pyrophosphate- or phosphide-based iron/cobalt electrocatalysts were prepared from the metal (R,S)-2-hydroxyphosphonoacetates to evaluate the effects of metal composition, N-doping and P-enrichment on the electrocatalytic activity. The crystalline and amorphous phases present in the electrocatalyst were identified and quantified by Rietveld and pair distribution function analyses. Differential PDF analysis of the spent catalysts revealed that, irrespectively of the amorphous or crystalline nature, all pyrolyzed solids transformed under OER operation into biphasic CoO(OH), composed of discrete clusters (size ≤ 20 Å). Fe-doping of cobalt electrocatalysts resulted in improved OER performances (overpotential of 270 mV at 10 mA·cm-2), attributable to the formation of electroactivity-enhanced solid solutions. Increasing the o-CoP proportion in cobalt phosphide electrocatalysts by addition of phosphonoacetic acid led to the lowest HER overpotential (140 mV). Moreover, amorphous Fe-doped cobalt pyrophosphate and phosphide-based electrocatalysts, employed as anode, showed a cell voltage of 1.58 V, at 10 mA·cm-2, in alkaline water splitting.

Keywords: Cobalt phosphonates/pyrophosphates/phosphides, Electrocatalysts, PDF analysis, OER/HER/ORR, water splitting

Suggested Citation

Vílchez-Cózar, Álvaro and Colodrero, Rosario M.P. and Bazaga-García, Montse and Marrero-López, David and El-refaei, Sayed M. and Russo, Patricia A. and Pinna, Nicola and Olivera-Pastor, Pascual and Cabeza Díaz, Aurelio, Structure-Activity Correlations of Phosphorous-Containing Cobalt Electrocatalysts: Insights into the Local Order by Pair Distribution Function Analysis. Available at SSRN: https://ssrn.com/abstract=4395102 or http://dx.doi.org/10.2139/ssrn.4395102

Álvaro Vílchez-Cózar

affiliation not provided to SSRN ( email )

No Address Available

Rosario M.P. Colodrero

affiliation not provided to SSRN ( email )

No Address Available

Montse Bazaga-García

affiliation not provided to SSRN ( email )

No Address Available

David Marrero-López

affiliation not provided to SSRN ( email )

No Address Available

Sayed M. El-refaei

affiliation not provided to SSRN ( email )

No Address Available

Patricia A. Russo

Humboldt University of Berlin ( email )

Nicola Pinna

Humboldt University of Berlin ( email )

Pascual Olivera-Pastor

affiliation not provided to SSRN ( email )

No Address Available

Aurelio Cabeza Díaz (Contact Author)

affiliation not provided to SSRN ( email )

No Address Available

Do you have a job opening that you would like to promote on SSRN?

Paper statistics

Downloads
40
Abstract Views
169
PlumX Metrics