Synthesis-sequence-controlled surface and electronic structure in Pd–Ag–Ni(OH)2/C electrocatalysts for efficient formic acid oxidation
Synthesis-sequence-controlled surface and electronic structure in Pd–Ag–Ni(OH)2/C electrocatalysts for efficient formic acid oxidation
The development of efficient and durable electrocatalysts for the formic acid oxidation reaction (FAOR) is central to the progress of direct formic acid fuel cells (DFAFCs). Here, we investigate how the synthesis sequence and reduction pathway influence the surface and electronic structure of PdAgNi(OH)2/C nanocomposites and, consequently, their FAOR performance in acidic media. Binary Pd/Ni(OH)2 catalysts with Pd/Ni(OH)2 mass ratios of 30:70, 50:50, and 70:30 were first screened, revealing 50:50 as the optimal composition. Partial substitution of Pd by Ag (Pd40Ag10 and Pd30Ag20 on Ni(OH)2(50)/C) was then combined with either sequential or simultaneous NaBH4-assisted reduction. Structural characterization by XRD, TEM, and XANES/EXAFS show that simultaneous coreduction tightens the Pd–Ag–Ni interfacial coupling, enhances Pd dispersion, and increases the contribution of Pd–O and Pd–Ni scattering paths, indicative of strong metal–oxide interactions. Electrochemical measurements demonstrate that the Pd30Ag20Ni(OH)2(50)/C catalyst prepared by simultaneous reduction exhibits the highest mass activity toward FAOR (6164 mA mgPd–1), a ca. 23-fold enhancement over commercial Pd/C, together with improved stability under potential cycling. These results demonstrate that controlling the synthesis sequence is an effective method for tuning the interfacial electronic structure of multicomponent Pd-based catalysts, providing practical guidelines for designing FAOR electrocatalysts for DFAFCs and related liquid-fuel energy conversion devices.
29603-29613
Argôlo, Maria E.S.C.
dba87140-3efe-4566-a340-9a3580576904
Almeida, Caio V.S.
718ae32a-23a1-4a8d-8248-a66d6f96f5fc
Sherwin, Connor
b4e01340-ac4d-46a3-8904-ec306c903761
Russell, Andrea E.
b6b7c748-efc1-4d5d-8a7a-8e4b69396169
Eguiluz, Katlin I.B.
59d40318-d101-44e0-b00c-b8f30aa1baf4
Salazar-Banda, Giancarlo R.
80800367-cb82-42ad-8137-83e98dbf4ecb
26 May 2026
Argôlo, Maria E.S.C.
dba87140-3efe-4566-a340-9a3580576904
Almeida, Caio V.S.
718ae32a-23a1-4a8d-8248-a66d6f96f5fc
Sherwin, Connor
b4e01340-ac4d-46a3-8904-ec306c903761
Russell, Andrea E.
b6b7c748-efc1-4d5d-8a7a-8e4b69396169
Eguiluz, Katlin I.B.
59d40318-d101-44e0-b00c-b8f30aa1baf4
Salazar-Banda, Giancarlo R.
80800367-cb82-42ad-8137-83e98dbf4ecb
Argôlo, Maria E.S.C., Almeida, Caio V.S., Sherwin, Connor, Russell, Andrea E., Eguiluz, Katlin I.B. and Salazar-Banda, Giancarlo R.
(2026)
Synthesis-sequence-controlled surface and electronic structure in Pd–Ag–Ni(OH)2/C electrocatalysts for efficient formic acid oxidation.
ACS Omega, 11 (20), .
(doi:10.1021/acsomega.5c12585).
Abstract
The development of efficient and durable electrocatalysts for the formic acid oxidation reaction (FAOR) is central to the progress of direct formic acid fuel cells (DFAFCs). Here, we investigate how the synthesis sequence and reduction pathway influence the surface and electronic structure of PdAgNi(OH)2/C nanocomposites and, consequently, their FAOR performance in acidic media. Binary Pd/Ni(OH)2 catalysts with Pd/Ni(OH)2 mass ratios of 30:70, 50:50, and 70:30 were first screened, revealing 50:50 as the optimal composition. Partial substitution of Pd by Ag (Pd40Ag10 and Pd30Ag20 on Ni(OH)2(50)/C) was then combined with either sequential or simultaneous NaBH4-assisted reduction. Structural characterization by XRD, TEM, and XANES/EXAFS show that simultaneous coreduction tightens the Pd–Ag–Ni interfacial coupling, enhances Pd dispersion, and increases the contribution of Pd–O and Pd–Ni scattering paths, indicative of strong metal–oxide interactions. Electrochemical measurements demonstrate that the Pd30Ag20Ni(OH)2(50)/C catalyst prepared by simultaneous reduction exhibits the highest mass activity toward FAOR (6164 mA mgPd–1), a ca. 23-fold enhancement over commercial Pd/C, together with improved stability under potential cycling. These results demonstrate that controlling the synthesis sequence is an effective method for tuning the interfacial electronic structure of multicomponent Pd-based catalysts, providing practical guidelines for designing FAOR electrocatalysts for DFAFCs and related liquid-fuel energy conversion devices.
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Accepted/In Press date: 5 May 2026
e-pub ahead of print date: 12 May 2026
Published date: 26 May 2026
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Local EPrints ID: 513693
URI: https://eprints.soton.ac.uk/id/eprint/513693
ISSN: 2470-1343
PURE UUID: 9788f1e2-9c88-4b8a-9008-94fabf68abd5
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Date deposited: 25 Aug 2026 16:31
Last modified: 13 Sep 2026 15:50
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Author:
Maria E.S.C. Argôlo
Author:
Caio V.S. Almeida
Author:
Connor Sherwin
Author:
Katlin I.B. Eguiluz
Author:
Giancarlo R. Salazar-Banda
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