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The present study outlines the transformation of non-photoresponsive hexagonal boron nitride (HBN) into a visible-light-responsive material. The carbon modification was achieved through a solid-state reaction procedure inside a tube furnace under nitrogen atmosphere. In comparison to HBN (bandgap of 5.2 eV), the carbon-modified boron nitride could efficiently absorb LED light irradiation with a light harvesting efficiency of ≈90% and a direct bandgap of 2 eV. The introduction of carbon into the HBN lattice led to a significant change in the electronic environment through the formation of C–B and C–N bonds which resulted in improved visible light activity, lower charge transfer resistance, and improved charge carrier density (2.97 × 1019 cm−3). This subsequently enhanced the photocurrent density (three times) and decreased the photovoltage decay time (two times) in comparison to those of HBN. The electronic band structure (obtained through Mott–Schottky plots) and charge trapping analysis confirmed the dominance of e−, O2−•, and •OH as dominant reactive oxygen species. The carbon modification could effectively remove 93.83% of methylene blue (MB, 20 ppm solution) and 48.56% of phenol (10 ppm solution) from the aqueous phase in comparison to HBN which shows zero activity in the visible region.

Herein, we report a detailed study on creating heterojunction between graphitic carbon nitride (g-C3N4) and bismuth phosphate (BiPO4), enhancing the unpaired free electron mobility. This leads to an accelerated photocatalysis of 2,4-dichlorophenols (2,4-DCPs) under sunlight irradiation. The heterojunction formation was efficaciously conducted via a modest thermal deposition technique. The function of g-C3N4 plays a significant role in generating free electrons under sunlight irradiation. Together, the generated electrons at the g-C3N4 conduction band (CB) are transferred and trapped by the BiPO4 to form active superoxide anion radicals (•O2-). These active radicals will be accountable for the photodegradation of 2,4-DCPs. The synthesized composite characteristics were methodically examined through several chemical and physical studies. Due to the inimitable features of both g-C3N4 and BiPO4, its heterojunction formation, 2.5wt% BiPO4/g-C3N4 achieved complete 2,4-DCP removal (100%) in 90 min under sunlight irradiation. This is due to the presence of g-C3N4 that enhanced electron mobility through the formation of heterojunctions that lengthens the electron-hole pairs' lifetime and maximizes the entire solar spectrum absorption to generate active electrons at the g-C3N4 conduction band. Thus, this formation significantly draws the attention for future environmental remediation, especially in enhancing the entire solar spectrum's harvesting.

The revolution in the arena of functional materials for the development of well advanced engineered photocatalyst can efficiently harness photon energy from a wide spectrum of electromagnetic radiation. These next-generation smart materials would be a spectacular approach in designing devices such as photovoltaic cells, photoelectrochemical cells, and photocatalytic fuel cells. Photocatalytic oxidation of water or wastewater for concurrent production of hydrogen and electric current has turned out as a principal concept for the construction of modern photocatalytic fuel cells (PFCs). Such PFCs mimics reverse photosynthesis process where electrical energy is generated from organic pollutants. In recent years many reviews on focusing the design, fabrication, and theoretical efficiency of the PFCs have been published. Hence the present review is aimed to unveil the wall-to-wall information starting from fundamentals spanning to working principles, structural configuration, electrochemical degradation of pollutants and photoelectrochemical properties, electron transport, thermodynamic behavior and columbic efficiency of studied PFCs.

TiO2 nanorods (NRs) have been successfully synthesized via simple hydrothermal technique utilizing TiCl4 as precursor at varied temperature of 160 °C, 200 °C and 250 °C, respectively. Further, thermal treatment was done in the close system at calcinations temperature thrice of the synthesis temperature. The prepared NRs were well characterized for the various physio-chemical natures of the materials. Crystallographic and morphological investigations showed that the samples exhibited high crystallinity with diameter ranges from 300 to 400 nm and length in several micrometers. XPS analysis proved the existence of oxygen defects that were created during the synthesis. The solar photocatalysis showed 81.27%, 92.20% and 58.79% removal of color by NR1, NR2 and NR3, respectively, within 300 min of direct sun irradiation time. The first-order kinetic model fits the better curve with the correlation coefficients of 0.97509, 0.97608 and 0.98417, respectively. Trapping experiments shows the dominant of holes and superoxide as the primary reactive oxygen species.

A facile hydrothermal route was followed to obtain a ternary composite Ag@AgVO

Solar-driven water splitting is one amongst the fastest growing areas of research for hydrogen evolution. The technology employs application of nanostructured energy materials with featured charge-separation and light absorption characteristics. The high charge-carrier recombination and wide band-gap of energy materials are major material-related bottlenecks that restricted the large-scale implementation. Besides it, the co-catalyst, electron mediator and sacrificial electron donor (SED) were the other major components for further improving the H2 yield. A water splitting reactor with well-optimized photon and mass transfer properties is mandatory for studying hydrogen evolution at large scale. The present review compiles various strategies that were presented for reducing charge-carrier recombination and extending visible light absorption of materials, insights for loading earth-abundant co-catalysts on photocatalyst surface, recently developed reversible redox and non-noble metal-based solid-state electron mediators and advantage of applying organic contaminant and biomass-derived waste as SEDs. The discussions on several engineered reactor designs for the photocatalytic water splitting technology were also presented. A cost-effective way of designing a photocatalytic water splitting system with functionalized nanostructured energy materials, the earth-abundant co-catalysts, organic waste-based electron donors and efficient electron mediators for achieving improved hydrogen evolution rate is comprehensively discussed.

3-D highly conductive polyvinyl formaldehyde sponges functionalized with acrylamide are fabricated using polyvinyl alcohol with varying concentrations of graphite nanopowder. The properties of the fabricated anodes are analyzed and its application in microbial fuel cells is evaluated. A comparative study with Graphite felt is also performed to evaluate its commercial viability. The presence of Hydroxyl and Amine functional groups enhanced the hydrophilic and biocompatible nature of the synthesized anodes. The phylogenetic analysis substantiated the biocompatible nature and mercury porosimetry showed macroporous nature of the fabricated anode. The highest power density of ~8 W/m2 is recorded for C10 establishing solid biofilm formation. A ~94% COD removal revealed the versatility of the anode for MFC based wastewater treatment. The MFC performance was twice than that of control and was also highest among the most reported modified 3-D anodes. The durability study displayed the commercial opportunity of the anode for real-time MFC operation.

C-Dots obtained from a sustainable route (melon-rinds were used as the source) were combined with TiNRs to create a composite via a simple hydrothermal technique. The obtained materials were subjected to analyses viz. FESEM, XRD, Raman spectroscopy, XPS, PL, FTIR and UV-vis-DRS for understanding their intrinsic nature. The solar photocatalytic performance was evaluated by the degradation of methyl orange (MO) as a model pollutant. The optical properties indicated that there was a clear redshift in the composite with a band gap of 2.49 eV, while the XRD results corresponded to a calculated crystalline size of 24.80 nm. The PL analysis proved the role of C-dots as an electron surge to the TiNRs. The photocatalytic reaction was faster with C-dots as compared to the solo TiNR with a higher degradation of 93.3% within 150 min obeying pseudo-first order kinetics with a rate constant k = 0.01723 min−1. The charge carrier scavenging investigation showed the role of numerous reactive oxygen species (ROS) on the degradation of MO. The formulated composite has demonstrated its ability in effectively handling the contaminants in water. Thus, this study establishes the two-step thermal method as an easy, facile, environmentally-friendly, and low-cost synthesis method for the large-scale production of a photocatalyst.

The thin film nanocomposites (TFN) based membranes are sensitive to the synergy between the polymer and nanoparticles. TFN incorporating metal-organic frameworks (MOFs) have shown tremendous enhancement in permeability. This study investigates alternate MOF positioning during TFC fabrication for a highly selective membrane. Co-Zn-based mixed metal-organic framework (mMOF) was interlayered between m-phenylenediamine (MPD) and trimesoyl chloride (TMC) to form a polyamide (PA) selective layer. The practiced method conveniently allowed exact loading of mMOF and thus prevented the loss. Owing to the mMOF's placement between MPD and TMC, an increase in PA cross-linking was observed. The mMOF-MPD monomer compatibility allowed homogeneous distribution and formation of a defect-free PA layer. The surface morphology showed a more pronounced formation of leaves-like features due to interfacial degassing. Neutral solute-based filtration tests determined mean pore size, probability distribution, and MWCO. The incorporation of mMOF led to formation of additional nanochannels in the membrane surface. The perm-selectivity studies performed on a dead-end filtration unit resulted in 94% As