Solar Hydrogen Production by Amorphous Silicon Photocathodes Coated with a Magnetron Sputter Deposited Mo₂C Catalyst

Abstract

Coupling of Earth-abundant hydrogen evolution catalysts to photoabsorbers is crucial for the production of hydrogen fuel using sunlight. In this work, we demonstrate the use of magnetron sputtering to deposit Mo2C as an efficient hydrogen evolution reaction catalyst onto surface-protected amorphous silicon (a-Si) photoabsorbers. The a-Si/Mo2C photocathode evolves hydrogen under simulated solar illumination in strongly acidic and alkaline electrolytes. Onsets of photocurrents are observed at potentials as positive as 0.85 V vs RHE. Under AM 1.5G (1 sun) illumination, the photocathodes reach current densities of -11.2 mA cm(-2) at the reversible hydrogen potential in 0.1 M H2SO4 and 1.0 M KOH. The high photovoltage and low-cost of the Mo2C/a-Si assembly make it a promising photocathode for solar hydrogen production.

Enhanced Electrocatalytic Activity for Water Splitting on NiO/Ni/Carbon Fiber Paper

“…Obviously the specific current density of the NiO/Ni/C sample is indeed higher than that of the ALD-NiO/C and Ni/C samples under a certain applied voltage, in which the current densities for the NiO/Ni/C samples of 10 mA·cm −2 and 100 mA·cm −2 are achieved at low overpotential vs. the reversible hydrogen electrodes (RHE) of 189 and 337 mV, respectively. The overpotential of NiO/Ni nanoparticles loaded at carbon fiber paper at 10 mA·cm −2 is smaller than most recently reported HER catalysts in alkaline solution [18,19,20,21,22,23,24,25,26], including CoNx/C (247 mV) [19], NiFe layered double hydroxide (LDH)/Ni foam (210 mV) [21], CoP/CC (209 mV) [24], and N-Co@G (337 mV) [26]. The highest HER activity of the NiO/Ni/C sample results from the NiO/Ni nanoparticles during the annealing process with reduction and mild oxidation treatment.…”

A one-dimensional porous carbon-supported Ni/Mo2C dual catalyst for efficient water splitting

“…Meanwhile, the η value required to reach a current density of 10 mA cm –2 ( η 10 ) is 179 mV for Ni/Mo 2 C-PC, which is 59 and 96 mV smaller than that of Mo 2 C-PC and Ni-PC, respectively. Strikingly, the onset potential and η 10 mean that the Ni/Mo 2 C-PC catalyst also performs superiorly to most documented non-noble-metal catalysts in basic electrolytes, such as Co–P/Co–PO 4 , 41 Co-NRCNTs, 42 WN array, 43 Mo 2 C, 44 CoO x @CN, 45 CoP array, 46 NiFe LDH/Ni foam, 33 and so on (Table S1, ESI†). For the physical mixture of Mo 2 C-PC and Ni-PC, its HER activity was located between those of its counterpart catalysts and was substantially inferior to that of the Ni/Mo 2 C-PC catalyst, suggesting that the strong chemical coupling effect works in the Ni/Mo 2 C-PC composite catalyst.…”

Strategies for Semiconductor/Electrocatalyst Coupling toward Solar‐Driven Water Splitting

“…The sweep rate is 5 mV s −1 . Reproduced with permission . Copyright 2015, The American Chemical Society.…”

“…While the co‐sputtered Mo 2 C demonstrated very good long‐term stability in 1.0 m KOH solution, the photocurrent density of Mo 2 C/TiO 2 /AZO/a‐Si photocathode was found to decrease gradually over time, which could be attributed to instability of TiO 2 and AZO layers in the corrosive alkaline electrolyte. The researchers proposed that a better stability could be achieved by improving the crystallinity of TiO 2 or introducing a more corrosion‐resistant Mo interlayer …”