High-performance vertically aligned Bi2O3 nanosheet arrays for water splitting applications by controlling the chemical bath deposition method parameters (precursor concentration and pH)

Revealing the Intrinsic Restructuring of Bi2O3 Nanoparticles into Bi Nanosheets during Electrochemical CO2 Reduction

“…Here, the stability of the NPs during washing with the water/acetone mixture is likely due to the high acetone content as we have shown that the catalysts restructure moderately in Milli-Q water (Figure 1b). We also note the consistency of our results with previous synthesis work where Bi 2 O 3 nanoparticles 42−45 synthesized at pH of 9 or 10 became transformed into larger spherical blocks, 42 longer platelets, 43 nanoparticle aggregate blocks, 44 and large-sized nanosheets 45 when the solution pH is raised. Therefore, the precatalyst restructuring appears to be associated with the electrolyte.…”

Reduced TiO2 Nanorods Decorated with Carbon Nanodots for Photoelectrochemical Water Oxidation

“…EIS measurements were performed to gain insight into the charge-transfer mechanism at all photoelectrodes. From the impedance spectra, two apparent semicircles were observed (Figure 6B), which is consistent with those reported for semiconductors such as Fe 2 O 3 , 59 BiVO 4 , 60 Bi 2 O 3 , 61 TiO 2 , 62 and so forth. In the case of TiO 2 and TiO 2 -Red, the two semicircles are easily distinguishable, but in the case of TiO 2 -CND and TiO 2 -Red-CND, an overlapping of the two semiarcs was observed.…”

“…Concerning R S (associated with the series resistances of the electrolyte and the substrate/semiconductor), no differences between the photoelectrodes are expected, but the observed variations are within the usual values for impedance measurements and are related to small changes in the distance between electrodes. 60,63 The increase of C SC in photoelectrodes with CND incorporation could be attributed to the formation of the heterojunction between TiO 2 and carbon nanodots. In fact, this increase is responsible for the overlapping of the two semiarcs in the Nyquist plot, since it is known that when the magnitude of C SC becomes equal to or greater than that of C SS , a single semicircle is observed.…”

“…As previously reported, the oxidation kinetics of water on the semiconductor produces the low-frequency semicircle. The high-frequency semicircle is related to the charge transport within the photoelectrode. , To analyze the experimental data, the results were fitted to the equivalent circuit (EC) shown in Figure A, which has been widely used to study charge-transfer mechanisms in metal oxide photoelectrodes. − The EC consists of the space-charge capacitance ( C SC ) of the bulk of TiO 2 , the charge-transport resistance ( R B ) from the bulk of TiO 2 to the surface states of TiO 2 or from the bulk of TiO 2 to the CND, the surface-state capacitance ( C SS ) resulting from the surface structure of TiO 2 or from the presence of CND, and the charge-transfer resistance at the photoelectrode-electrolyte interface ( R CT ). The fitted impedance parameters are listed in Table .…”