Evaluation of Pt, Ni, and Ni–Mo electrocatalysts for hydrogen evolution on crystalline Si electrodes

Abstract

The dark electrocatalytic and light photocathodic hydrogen evolution properties of Ni, Ni-Mo alloys, and Pt on Si electrodes have been measured, to assess the viability of earth-abundant electrocatalysts for integrated, semiconductor coupled fuel formation. In the dark, the activities of these catalysts deposited on degenerately doped p + -Si electrodes increased in the order Ni < Ni-Mo # Pt. Ni-Mo deposited on degenerately doped Si microwires exhibited activity that was very similar to that of Pt deposited by metal evaporation on planar Si electrodes. Under 100 mW cm À2 of Air Mass 1.5 solar simulation, the energy conversion efficiencies of p-type Si/catalyst photoelectrodes ranged from 0.2-1%, and increased in the order Ni z Ni-Mo < Pt, due to somewhat lower photovoltages and photocurrents for p-Si/Ni-Mo relative to p-Si/Ni and p-Si/Pt photoelectrodes. Deposition of the catalysts onto microwire arrays resulted in higher apparent catalytic activities and similar photoelectrode efficiencies than were observed on planar p-Si photocathodes, despite lower light absorption by p-Si in the microwire structures.

An analysis of the optimal band gaps of light absorbers in integrated tandem photoelectrochemical water-splitting systems

“…Band gap combinations of 1.65-1.80 eV/1.12 eV are practical. Si (1.12 eV) photocathodes with Pt 37,38 and NiMo 39,40 catalysts have been demonstrated with efficiencies approaching their bulk recombination limit. Substantial efforts should be devoted to the search for topjunction materials having a 1.65-1.8 eV band gap, which is current-matched to the bottom Si photoelectrodes in such a system.…”

Net primary energy balance of a solar-driven photoelectrochemical water-splitting device

“…6,26 Both reactions could use catalysts to make the reactions more efficient. [26][27][28] A PEC device also requires a transparent cover, a support structure, and encapsulation.…”

Photoelectrochemical Hydrogen Production in Alkaline Solutions Using Cu2O Coated with Earth‐Abundant Hydrogen Evolution Catalysts

“…Faradaic efficiencies were measured in a gastight, home-made H cell calibrated for pressure and gas quantification previously reported. [1][2] The Ni-Mo catalyst loading on FTO was estimated using the modified anodic stripping voltammetry technique previously reported by Mckone et al [3] The deposition charge efficiency can be determined by integrating the charges passed during anodic stripping of the Ni-Mo catalyst immersed in 1.0 M H 2 SO 4 and comparing this value to the total charges passed during electrodeposition of the catalyst. This gives a lower limit due to the fast dissolution of the catalyst in acid that is not coupled to electron transfer from the electrode.…”