Enhanced Solar‐Photo(Electro)catalysis of Microwave‐Hydrothermal Synthesized BiVO₄, ms‐BiVO₄/Reduced Graphene Oxide/Ag₃PO₄ Nanohybrid: Crystalline Phase‐Dependent Interfacial Charge Carrier Dynamics

Abstract

Bismuth vanadate with reduced graphene oxide (BiVO4/RGO) is prepared via ultrafast, energy‐efficient microwave‐assisted hydrothermal technique. Subsequently, Ag3PO4 nanoparticles are decorated on BiVO4/RGO by impregnated solution process. Photoelectrochemical (PEC) performance is carried out using as‐synthesized ternary heterostructure ms‐BiVO4/RGO/Ag3PO4 nanohybrid photoanode film and Pt‐wire as cathode in 0.5 m Na2SO4 electrolyte solution under AM 1.5 G (100 mW cm−2) irradiation. An enhanced photocurrent density of ≈3.6 mA cm−2 at +1.23 VRHE is observed for water oxidation, which is ≈2.3 times higher than pristine ms‐BiVO4 (1.58 mA cm−2). Furthermore, 10.1% of incident light‐to‐photocurrent conversion at λ = 450 nm and improved solar‐to‐hydrogen conversion efficiency of 4.5% with consistent photostability up‐to 24 h is achieved. While Rhodamine‐B dye degradation is investigated using BiVO4/RGO/Ag3PO4 photocatalyst, offers highest visible‐light‐driven photocatalytic (PC) degradation with average rate constant of kavg = 1.70 × 10−1 min−1 in 20 min, ≈4.3 times higher than pristine ms‐BiVO4. Such enhancement in PEC and PC performances is due to improved light absorbance coefficient with extended hole diffusion length (LPEC/PC = 209/147 nm) that enables efficient interfacial charge separation, transportation, and reduced photoinduced recombination. Herein, a strategy of designing an efficient nanohybrid photo(electro)catalyst to generate H2 fuel from water oxidation process and for environmental remediation is developed.

Revealing the effect of substitutional cation doping in the A-site of nanoscale APbI3 perovskite layers for enhanced retention and endurance in optoelectronic resistive switching for non-volatile bipolar memory devices

“…Subsequently, the velocity of the dipoles in the precursor mixture was also increased as they tried to align with the oscillating electromagnetic field provided by the reactor system. 54 Thus, adequate thermal energy was created that facilitated the creation of “hot spots” that favoured burst nucleation as in the case of La Mer crystallization. 50 Accordingly, the electromagnetic radiation, directly interacts with the reactants, thereby creating an energetic coupling at the molecular level, thus further enhancing the growth of the APbI 3 metal halide perovskite powders.…”

“…50 Accordingly, the electromagnetic radiation, directly interacts with the reactants, thereby creating an energetic coupling at the molecular level, thus further enhancing the growth of the APbI 3 metal halide perovskite powders. 53,54 For a typical APbI 3 metal halide perovskite synthesis, the conversion of reactants into their final products occurs as shown in eqn (1.7).Pb(Ac) 2 + 3HI + CH 3 NH 2 /A(Ac) 2 → APbI 3 + CH 3 COOH…”

“…It could also be noted that, lesser Δ G ‡ indicates the requirement of less energy for initiating the reaction and the negative value of Δ S ‡ indicates the coherently directed energy that is utilized for the reaction without dissipation or scattering. 54 The lowest Δ S ‡ obtained for CsMAFAPI denotes the formation of a stable structure of the product, hindering the molecular movement and thereby reducing randomness. 55 Table 3, tabulates the estimated thermodynamic parameters obtained for the MW-ST synthesized APbI 3 perovskites.…”

Ultrastable, High Photoelectrocatalytic Performance of Altervalent Cation-Doped BiVO4 Photoanode and Effect of Interfacial Contact with Nanoporous Carbon for Seawater Splitting Using a 3D-Printed Flow Device

“…18,19 Recently, we have successfully demonstrated that the hybrid heterostructure of ms-BiVO 4 /RGO/Ag 3 PO 4 showed significant PEC performance by way of an enhanced photocurrent density of 3.6 mA cm −2 with a retention of 24 h, which is 2.3-folds greater than that of pristine ms-BiVO 4 , owing to the enhanced hole diffusion length and minority carrier lifetime. 20 Upon heteroatom doping in the BiVO 4 , leading to effective tuning of valence band (VB) and conduction band (CB) positions of the BiVO 4 photoelectrodes, since the band edge positions substantially determine the redox competence of the photogenerated charge carriers, it directly affects the efficiency of the PEC performance. 19 Moreover, multiple-ion doping into either the A-site or B-site or both sites in the ABO 4 scheelite structure of BiVO 4 has been explored for the superior tunability of the VB and CB electronic structures.…”

“…In our recent study, we established the impact of reduced graphene oxide (RGO) as an excellent electron-shuttling mediator with a large specific surface area on ms-BiVO 4 /RGO/Ag 3 PO 4 hybrid photoanode for enhanced PEC activity in freshwater. 20 Indeed, it is expected that the hybrid photoanode surface enhances the electron transfer kinetics at their interface due to the delocalized electrons from the conjugated sp 2 -bonded carbon with a 2-D electronically conductive pathway and the presence of active electrochemical sites, which may benefit direct seawater electrolysis. 36 However, fundamental knowledge on the electronic structure, site-selective doping, oxygen vacancies (OV), and space-charge layer width that could be of benefit to obtain substantially proficient BiVO 4 photoelectrodes remains unexplored.…”