Nanostructured δ-MnO₂/Cd(OH)₂ Heterojunction Constructed under Ambient Conditions as a Sustainable Cathode for Photocatalytic Hydrogen Production

Abstract

In this study, we report the deposition of a thin layer of Cd­(OH)2 over δ-MnO2 deposited on a fluorine-doped tin oxide (FTO) glass substrate, thereby forming a heterojunction with synergistic effects. Electrodes fabricated by a room-temperature, facile, and cost-effective chemical bath deposition method display enhanced photoactivity when used as cathodes for the hydrogen evolution reaction (HER) in a photoelectrochemical cell, with an observed photocurrent of 0.3 mA/cm2 at 0 V vs reversible hydrogen electrode (RHE). The electrodes also showcase a dark electrocatalytic current of 2.9 mA/cm2 without illumination. The δ-MnO2/Cd­(OH)2 nano-heterostructure is analyzed thoroughly via various physicochemical, optical and electrochemical methods to understand the phenomena involved in the conduction characteristics. The enhanced photoconductivity is attributed to effective charge separation and transport by the presence of synergistic materials with optimal band gap energies. These results show promise for the use of birnessite-based materials as sustainable electro- or photocatalysts for the hydrogen evolution reaction.

Construction of a BiOCl/Bi2O2CO3 S-Scheme Heterojunction Photocatalyst via Sharing [Bi2O2]2+ Slabs with Enhanced Photocatalytic H2O2 Production Performance

“…It could be seen that the B/BC-162 composite photocatalyst accumulates a large number of photogenerated carriers in a short period, and it is inferred that B/BC-162 has significant photogenerated electron and hole separation ability. , This conclusion is reconfirmed by the results of electrochemical impedance spectroscopy (EIS) tests, as illustrated in Figure b. In comparison to Bi 2 O 2 CO 3 and BiOCl, B/BC-162 displayed the smallest arc radius in the Nyquist plots, which demonstrated its lower charge transfer resistance and effective charge transfer and separation. , …”

“…In comparison to Bi 2 O 2 CO 3 and BiOCl, B/BC-162 displayed the smallest arc radius in the Nyquist plots, which demonstrated its lower charge transfer resistance and effective charge transfer and separation. 49,50 Figure 8c shows the photoluminescence (PL) spectra of Bi 2 O 2 CO 3 , BiOCl, and B/BC-162. It is clear that a decrease in PL intensity is usually associated with a reduced carrier recombination probability.…”

Experimental and theoretical study on hydrogen production by using Ag nanoparticle‐decorated graphite/Ni cathode

“…We need an alternative, renewable, sustainable, and clean energy sources such as hydrogen energy which is abundantly available and produces no emission during consumption 1,2 . Indeed, hydrogen has been considered to be one of the promising energy source alternate to traditional fossil fuels in future for sustainable energy storage and conversion 3‐5 . We have many alternative hydrogen production methods such as thermochemical processes (ie, steam methane reforming, coal gasification, biomass gasification, etc.…”

“…1,2 Indeed, hydrogen has been considered to be one of the promising energy source alternate to traditional fossil fuels in future for sustainable energy storage and conversion. [3][4][5] We have many alternative hydrogen production methods such as thermochemical processes (ie, steam methane reforming, coal gasification, biomass gasification, etc. ), direct solar water splitting processes, biological processes (from bacteria and microalgae), alkaline water electrolysis, and so on.…”