Enhancing light harvesting and charge separation of Cu₂O photocathodes with spatially separated noble-metal cocatalysts towards highly efficient water splitting

Abstract

A feasible strategy of spatially separated noble-metal cocatalysts for Cu2O photocathodes to enhance light harvesting and charge separation.

3D Branched Ca‐Fe2O3/Fe2O3 Decorated with Pt and Co‐Pi: Improved Charge‐Separation Dynamics and Photoelectrochemical Performance

“…[29] As ac onsequence, the reduced onset potential and enhanced photocurrent density can be attributed to two factors. [31] Figure 4d shows that the order of the arc radius of EIS Nyquist plots is Ca-Fe 2 O 3 /Fe 2 O 3 BNRs < Ca-Fe 2 O 3 NRs < Fe 2 O 3 NRs, and the corresponding fittingr esults shown in Table S1 (Supporting Information) are 914,1 006, and 3820 W,r espectively.T he smallers emicircles for Ca-Fe 2 O 3 /Fe 2 O 3 BNRs and Ca-Fe 2 O 3 NRs than for bare Fe 2 O 3 indicate the faster charge-transfer and -separation kinetics benefited from the efficient hole extraction and decreased surface states. The other is that the homogeneous combination of n-type Fe 2 O 3 and p-type Ca-Fe 2 O 3 leads to as trongb uilt-in electric field, which brings about the cathodic shift in onset potential.…”

1D WO3 Nanorods/2D WO3−x Nanoflakes Homojunction Structure for Enhanced Charge Separation and Transfer towards Efficient Photoelectrochemical Performance

“…Since the pioneer TiO 2 photoelectrode was employed to split water,p hotoelectrochemical (PEC) water splitting based on semiconductor nanomaterials hasb een deemed ag reen strategy to transform solare nergy into usable hydrogen, which is becoming ah ot topic in the fields of energy and thee nvironment. [1][2][3] Hence, finding suitable semiconductor materials as photoelectrodes is of great importance to achieve efficient PEC water splitting. Transition-metal oxides( TMOs) have attracted considerable attention owing to their abundant nature,e xcellent environmental compatibility, and good chemical stability.…”

“…However,f ormation of excessive surface oxygen vacancies may occur during this process and lead to the introductiono fc arrier-recombination centers. Zhang et al [21] reported a2 DW O 3 nanoflakes (NFs) photoanode with suitable bulk oxygen vacancies and reduced surface oxygen vacancies throughh ydrogen treatment ando zone treatment, and the obtained photoanodes exhibited ap hotocurrentd ensity of 2.25 mA cm À2 (at 1.23 Vv s. RHE), which is approximately 2.06 times that of pristine WO 3 . In this work, the 2D nonstoichiometric WO 3Àx NFs were fabricated by ah ydrothermal methodo n1 DW O 3 nanorods (NRs) annealeda th igh temperature, and the 1D/2D composite structure was designed to improve carrier separation and transfer efficiency as well as light harvesting.…”

Cu2O Photocathode with Faster Charge Transfer by Fully Reacted Cu Seed Layer to Enhance Performance of Hydrogen Evolution in Solar Water Splitting Applications

“…Among materials used to produce hydrogen gas using PEC cells, Cu 2 O is a good candidate because it is costcompetitive and an abundant material in the earth. [10][11][12][13][14][15] Cu 2 O is a p-type semiconductor material with a band gap of 1.6-2.2 eV, absorbance in the visible light range (563-775 nm), and a suitable band edge alignment that is amenable for generating chemical energy. [16][17][18] In a PEC device, the absorbed sunlight at the Cu 2 O surface generates excited electrons by reducing protons to hydrogen gas at the interface between the photoelectrode and the electrolyte.…”

“…[16][17][18] In a PEC device, the absorbed sunlight at the Cu 2 O surface generates excited electrons by reducing protons to hydrogen gas at the interface between the photoelectrode and the electrolyte. [10,11,[13][14][15] Cu 2 O has a theoretical hydrogen conversion efficiency of 18 % in PEC cells and a power conversion efficiency of 20 % in a solar cell. [12,15] However, low hydrogen generation and instability are two challenges that prevent the usage of Cu 2 O as a photocathode in PEC cells.…”