Abstract
The development of earth-abundant transition metal-based catalysts, supported by a conductive carbonaceous matrix, has received great attention in the field of conversion of formaldehyde derivatives into toxic-free species. Herein, we report a comprehensive investigation of bimetallic electrocatalyst activity towards the electrooxidation of formaldehyde. The bimetallic phosphate catalyst is prepared by co-precipitation of Ni and Mn phosphate precursors using a simple reflux approach. Then the bimetallic catalyst is produced by mixing the Ni/Mn with carbon fibres (CNFs). The structural properties and crystallinity of the catalyst were investigated by using several techniques, such as scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and Brunauer Emmett−Teller theory. The system performance was studied under potentiostatic conditions. Some theoretical thermodynamic and kinetic models were applied to assess the system performance. Accordingly, key electrochemical parameters, including surface coverage (
Γ
) of active species, charge transfer rate (
k
s
), diffusion coefficient of the formaldehyde (
D
), and catalytic rate constant (
k
cat
) were calculated at
Γ
= 1.690 × 10
−4
mmol cm
−2
,
k
s
= 1.0800 s
−1
,
D
= 1.185 × 10
−3
cm
2
s
−1
and
k
cat
= 1.08 × 10
5
cm
3
mol
−1
s
−1
. These findings demonstrate the intrinsic electrocatalytic activity of formaldehyde electrooxidation on nickel/manganese phosphate- CNFs in alkaline medium.
The catalytic performance of bimetallic Ni/Mn phosphate–carbon nanofiber composite catalyst is better than mono metallic catalysts toward electrooxidation of formaldehyde.