Wittichenite semiconductor of Cu3BiS3 films for efficient hydrogen evolution from solar driven photoelectrochemical water splitting

Abstract

A highly efficient, low-cost and environmentally friendly photocathode with long-term stability is the goal of practical solar hydrogen evolution applications. Here, we found that the Cu3BiS3 film-based photocathode meets the abovementioned requirements. The Cu3BiS3-based photocathode presents a remarkable onset potential over 0.9 VRHE with excellent photoelectrochemical current densities (~7 mA/cm2 under 0 VRHE) and appreciable 10-hour long-term stability in neutral water solutions. This high onset potential of the Cu3BiS3-based photocathode directly results in a good unbiased operating photocurrent of ~1.6 mA/cm2 assisted by the BiVO4 photoanode. A tandem device of Cu3BiS3-BiVO4 with an unbiased solar-to-hydrogen conversion efficiency of 2.04% is presented. This tandem device also presents high stability over 20 hours. Ultimately, a 5 × 5 cm2 large Cu3BiS3-BiVO4 tandem device module is fabricated for standalone overall solar water splitting with a long-term stability of 60 hours.

Effective Charge Carrier Utilization of BiVO4 for Solar Overall Water Splitting

“… [24,25,73–76] Based on it, two typical BiVO 4 photoanode‐constituted PEC systems for OWS, that are photoanode‐photovoltaic cell and photoanode‐photocathode cell, have been developed with appreciable STH conversion efficiencies (summarized in Table 2). [18,23,77–85] The tandem devices composed of BiVO 4 and photovoltaic cells typically exhibited the STH efficiencies higher than 5 % and achieved the highest value of 8.1 % when connecting the WO 3 /BiVO 4 /Co−Pi heterojunction photoanode with a double junction GaAs/InGaAsP photovoltaic cell [18] . Kim et al.…”

“…constructed the hetero‐type dual photoanodes of BiVO 4 and α‐Fe 2 O 3 to extend the light absorption wavelength to 610 nm, and a tandem cell composed of the dual photoanodes‐silicon solar cell demonstrated an unbiased STH efficiency of 7.7 %, which was a significant step towards achieving the target of 10 % required for practical solar hydrogen production [77] . The second type of photoanode‐photocathode cell, which the BiVO 4 photoanode is integrated with an efficient photocathode (i. e., Cu 2 O, CuIn 0.5 Ga 0.5 Se 2 , Cu 3 BiS 3 , Cu 2 ZnSnS 4 , Si, organic polymer‐based photocathode), is another way to achieve unassisted PEC OWS [23,81–85] . The highest reported STH value was 4.3 %.…”

Hydrogen-substituted graphdiyne encapsulated cuprous oxide photocathode for efficient and stable photoelectrochemical water reduction

“…The PEC device with p -type semiconductor as photocathodes (with electron as photo-generated minority charge) can directly generate hydrogen on the surface of photoelectrodes through converting renewable and intermittent solar energy into chemical energy and storing in chemical bonds of hydrogen 4 . Currently, PEC water reduction is well developed with inorganic p -type semiconductors, such as silicon 5 , 6 , metal oxides 7 , 8 , metal phosphides 9 , and metal sulfides 10 , 11 . Cuprous oxide (Cu 2 O), a natural p -type semiconductor, owns a narrow direct bandgap of 2.0 eV, high theoretical photocurrent density of −14.7 mA cm −2 and photoconversion efficiency of 18%, suitable conduction band position (0.7 V higher than the hydrogen evolution potential), and earth-abundance and low cost 12 – 15 , all of these merits distinguish it to be one of the most promising photocathode candidates for PEC hydrogen generation.…”

Drastic improvement in photoelectrochemical water splitting performance over prolonged reaction time using new carrier-guiding semiconductor nanostructures

“…This result differs greatly from the signicant degradation in the PEC-WS performance over time reported in the literature. 32,33 The timedependent improvement in the performance of the PEC-WS is discussed in terms of the efficient carrier generation of the highly crystalline InGaN/GaN CSNWs, the carrier guiding effect of the new core-shell structure with the protruding core, and the protection the InGaN core is offered by the GaN shell from corrosion by the harsh electrolyte during the PEC-WS reaction. Fig.…”

“…This behaviour is quite different from the signicant degradation of the PEC-WS performance over time typically observed in previous studies. 32,33 The amount of hydrogen gas generated by the InGaN/GaN-CSNW PC, calculated from the current density (see ESI Note S2 †), reached a maximum of 22.15 mmol cm À2 aer operating the PEC-WS reaction for ten hours. It should be noted that the current density and the amount of hydrogen gas generated from the InGaN/GaN-CSNW PC are much higher than those that were previously reported for PCs comprising any kind of NWs, as listed in Table 1.…”