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The deployment of direct formate fuel cells (DFFCs) relies on the development of active and stable catalysts for the formate oxidation reaction (FOR). Palladium, providing effective full oxidation of formate to CO2, has been widely used as FOR catalyst, but it suffers from low stability, moderate activity, and high cost. Herein, we detail a colloidal synthesis route for the incorporation of P on Pd2Sn nanoparticles. These nanoparticles are dispersed on carbon black and the obtained composite is used as electrocatalytic material for the FOR. The Pd2Sn0.8P-based electrodes present outstanding catalytic activities with record mass current densities up to 10.0 A mgPd-1, well above those of Pd1.6Sn/C reference electrode. These high current densities are further enhanced by increasing the temperature from 25 °C to 40 °C. The Pd2Sn0.8P electrode also allows for slowing down the rapid current decay that generally happens during operation and can be rapidly re-activated through potential cycling. The excellent catalytic performance obtained is rationalized using density functional theory (DFT) calculations.

The development of high current density anodes for the oxygen evolution reaction (OER) is fundamental to manufacturing practical and reliable electrochemical cells. In this work, we have developed a bimetallic electrocatalyst based on cobalt–iron oxyhydroxide that shows outstanding performance for water oxidation. Such a catalyst is obtained from cobalt–iron phosphide nanorods that serve as sacrificial structures for the formation of a bimetallic oxyhydroxide through phosphorous loss concomitantly to oxygen/hydroxide incorporation. CoFeP nanorods are synthesized using a scalable method using triphenyl phosphite as a phosphorous precursor. They are deposited without the use of binders on nickel foam to enable fast electron transport, a highly effective surface area, and a high density of active sites. The morphological and chemical transformation of the CoFeP nanoparticles is analyzed and compared with the monometallic cobalt phosphide in alkaline media and under anodic potentials. The resulting bimetallic electrode presents a Tafel slope as low as 42 mV dec–1 and low overpotentials for OER. For the first time, an anion exchange membrane electrolysis device with an integrated CoFeP-based anode was tested at a high current density of 1 A cm–2, demonstrating excellent stability and Faradaic efficiency near 100%. This work opens up a way for using metal phosphide-based anodes for practical fuel electrosynthesis devices.

The development of high current density anodes for the oxygen evolution reaction (OER) is fundamental to manufacturing practical and reliable electrochemical cells. In this work, we have developed a bimetallic electrocatalyst based on cobalt-iron oxyhydroxide that shows outstanding performance for water oxidation. Such a catalyst is obtained from cobalt-iron phosphide nanorods that serve as sacrificial structures for the formation of a bimetallic oxyhydroxide through phosphorous loss concomitantly to oxygen/hydroxide incorporation. CoFeP nanorods are synthesized using a scalable method using triphenyl phosphite as a phosphorous precursor. They are deposited without the use of binders on nickel foam to enable fast electron transport, a highly effective surface area, and a high density of active sites. The morphological and chemical transformation of the CoFeP nanoparticles is analyzed and compared with the monometallic cobalt phosphide in alkaline media and under anodic potentials. The resulting bimetallic electrode presents a Tafel slope as low as 42 mV dec-1 and low overpotentials for OER. For the first time, an anion exchange membrane electrolysis device with an integrated CoFeP-based anode was tested at a high current density of 1 A cm-2, demonstrating excellent stability and Faradaic efficiency near 100%. This work opens up a way for using metal phosphide-based anodes for practical fuel electrosynthesis devices.

The lack of electrocatalysts for the formate oxidation reaction (FOR) hampers the deployment of direct formate fuel cells (DFFCs). To overcome this limitation, herein, we detail the production of palladium hydride particles supported on C2N (PdH0.58@C2N) via a facile method. PdH0.58@C2N displays excellent FOR performance, reaching current densities up to 5.6 A·mgPd–1 and stable cycling and chronoamperometric operation. The Pd lattice expands due to the hydrogen intercalation. Besides, an electronic redistribution associated with the distinct electronegativity of Pd and H is observed. Both phenomena modify the electron energy levels, enhancing the activity and stability of the composite catalyst. More specifically, differential functional theory calculations show H intercalation to downshift the Pd d-band center in Pd0.58@C2N, weakening adsorbate binding and accelerating the FOR rate-determining step.

The lack of electrocatalysts for the formate oxidation reaction (FOR) hampers the deployment of direct formate fuel cells (DFFCs). To overcome this limitation, herein, we detail the production of palladium hydride particles supported on C2N (PdH0.58@C2N) via a facile method. PdH0.58@C2N displays excellent FOR performance, reaching current densities up to 5.6 A·mgPd–1 and stable cycling and chronoamperometric operation. The Pd lattice expands due to the hydrogen intercalation. Besides, an electronic redistribution associated with the distinct electronegativity of Pd and H is observed. Both phenomena modify the electron energy levels, enhancing the activity and stability of the composite catalyst. More specifically, differential functional theory calculations show H intercalation to downshift the Pd d-band center in Pd0.58@C2N, weakening adsorbate binding and accelerating the FOR rate-determining step.