Constructing BiVO4/Graphene/TiO2 nanocomposite photoanode for photoelectrochemical conversion applications

Challenges and prospects about the graphene role in the design of photoelectrodes for sunlight-driven water splitting

Graphene and its derivatives have emerged as potential materials for several technological applications including sunlight-driven water splitting reactions. This review critically addresses the latest achievements concerning the use of graphene as a player in the design of hybrid-photoelectrodes for photoelectrochemical cells. Insights about the charge carrier dynamics of graphene-based photocatalysts which include metal oxides and non-metal oxide semiconductors are also discussed. The concepts underpinning the continued progress in the field of graphene/photoelectrodes, including different graphene structures, architecture as well as the possible mechanisms for hydrogen and oxygen reactions are also presented. Despite several reports having demonstrated the potential of graphene-based photocatalysts, the achieved performance remains far from the targeted benchmark efficiency for commercial application. This review also highlights the challenges and opportunities related to graphene application in photoelectrochemical cells for future directions in the field.

A novel BiVO4-GO-TiO2-PANI composite for upgraded photocatalytic performance under visible light and its non-toxicity

A novel non-toxic hybrid BiVO₄-GO-TiO₂-polyaniline (PANI) (BVGT-PANI) composite with superior photocatalysis was successfully prepared via a one-pot hydrothermal reaction. The structural and morphological characterizations of the synthesized compounds were analyzed by a series of techniques. We found excellent photocatalytic efficiencies for methylene blue (MB) and phenol degradation under visible light irradiation after adhering the PANI to the photocatalyst. The degradation rates of MB and phenol reach up to approximately 85% and 80%, respectively, after 3 h of irradiation. For photodegradation MB, BVGTA exhibit the highest k_app rate constant of about 1.06 × 10^-2 min^-1, which is about 1.63-fold faster than BVG and 2.94-fold faster than BVGT. For photodegradation of phenol, BVGTA exhibits the highest k_app rate constant, of about 8.86 × 10^-3min^-1, which is about 1.2-fold faster than BVG and 1.96-fold faster than BVGT. Furthermore, vitro toxicity test against Bacillus subtilis and Staphylococcus aureus demonstrated that the nanophotocatalyst is non-toxic.

TiO2/graphene/CuSbS2 mixed-dimensional array with high-performance photoelectrochemical properties

The growing demands for reproducible and clean sources of power has prompted the exploitation of novel materials for solar-energy conversion; in any case, the improvement of their conversion efficiency remains a big challenge.

Strongly Coupled Metal Oxide/Reassembled Carbon Nitride/Co-Pi Heterostructures for Efficient Photoelectrochemical Water Splitting

The photoelectrochemical application of carbon nitride is extremely exciting because of the meta-free components, low cost, nontoxicity, and appropriate band positions. To construct carbon nitride-based heterostructures, a conventional ultrasonic exfoliation method is usually used to fabricate dispersion of ultrathin nanosheets. However, the outstretched structure and the poor dispersity inevitably result in the poor interfacial contact between different materials. To solve this problem, hydrolyzed carbon nitride suspension was used as a homogeneous precursor for the fabrication of composite photoanodes. The in situ reassembly of one-dimensional nanofibers resulted in the formation of uniform and ultrathin carbon nitride nanoarchitectures on the surface of Fe₂O₃ nanorod arrays. Because of the strongly coupled interfaces and the deposition of Co-Pi water oxidation cocatalysts, the as-synthesized heterostructured photoanodes exhibited three-fold increased photocurrent density and good stability, compared to pristine Fe₂O₃. The significantly improved photoactivity of the Fe₂O₃/reassembled carbon nitride/Co-Pi heterostructures was ascribed to the decreased interfacial conductivity and facilitated charge separation. This material designing strategy was further used to construct TiO₂/carbon nitride, ZnO/carbon nitride, and WO₃/carbon nitride heterostructures. The incorporation of hydrolyzed carbon nitride could remarkably enhance the photoelectrochemical performance of these metal oxide photoanodes. Thus, this work provides a new paradigm for designing carbon nitride-based composite nanostructures for efficient and stable solar fuel production.