Speaker
Description
Driven by the necessity to mitigate the effects of climate changes, future economy will be increasingly dominated by renewable energy sources. In this context, hydrogen will play a fundamental role in the energy transition from fossil to green sources. This gas can be easily produced employing water electrolysis, which currently relies on the use of noble metal electrocatalysts (like platinum) to lower the overpotential required for the Hydrogen Evolution Reaction (HER) to take place. Due to their limited availability and consequent high cost, however, research is currently investigating low-cost alternatives like transition metal phosphides [1].
In the present work, cobalt phosphide layers were fabricated through a simple and costless codeposition-annealing process. A Co-P solid solution was codeposited with elemental phosphorus particles and subsequently annealed [2]. Annealing temperature was optimized to promote the formation of phosphides through interdiffusion between red phosphorus particles and the metallic matrix. The most important advantage of this methodology is the possibility to overcome the compositional limit typical of electrodeposited phosphorus-based alloys. This aspect is fundamental to obtain phosphorus-rich compounds, which present the highest catalytic activities [3]. Furthermore, the technique allows to confine phosphorus inside the coating during annealing, avoiding the need of phosphorization processes in dangerous P containing atmospheres.
Obtained layers were characterized to assess their morphology, phase structure and chemical composition. Their electrocatalytic properties were tested in 0.5 M sulfuric acid, obtaining remarkable results. The lowest observed overpotential was 62 mV vs. RHE (at 10 mA for square centimeter). This result is promising if compared to the literature available on cobalt phosphides electrocatalysts [4].
[1] Xiao et al., DOI: 10.1002/aenm.201500985
[2] Bernasconi et al., DOI: 10.1021/acsaem.0c00733
[3] Li et al., DOI: 10.1002/admi.202000676
[4] Saadi et al., DOI: 10.1021/jp5054452
| Speaker Country | Italy |
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