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Carbon-based materials that act as supports to design electrocatalysts have been actively pursued for fuel cells and overall water-splitting (OWS) applications. However, carbon-based supports face serious carbon corrosion at high positive potentials, affecting catalyst activity and stability and hindering practical applicability. Herein, carbon-free transition metal-oxide–based 2D titanate nanosheet support has been proposed, demonstrating the applicability of titanate nanosheets as an alternative support for designing electrocatalysts. A new chemical route to produce large 2D nanosheets of titanate via exfoliation has been discovered. Colloidal 2D titanate nanosheet support allows the growth of active nickel molybdenum oxide (NiMoOx) forming Titanate@NiMoOxcore–shell materials. Fine heat treatment at different temperatures facilitates in situformation of MoOxin NiMoOxlayers on 2D titanate boosting catalytic activity. An increase in heat treatment facilitates an increase in the semiconductivity of the titanate phase and a simultaneous decay of the active MoOxcomponent, resulting in poor activity. The optimal catalyst Titanate@NiMoOx_200 required an overpotential of 0.54 and 1.19 VRHEfor the HER and the OER and an overall cell voltage of 1.75 V to deliver a current density of 10 mA cm–2with spectacular stability for up to 24 h in KOH media. Spectroscopic and microscopy analyses prove the efficient electronic interaction between MoOxand NiMoOxin the hybrid components. Density functional theory and experimental work suggest that the MoOx/NiMoOxhybrid shows higher water adsorption energy and excellent water-splitting performance. This work sheds light on the feasibility and practical application of titanate support for the rational design of diverse electrocatalysts from noble to non-noble metal-based electrocatalysts for a range of electrochemical applications.

This study focuses on synthesizing CoP nanoparticles through the thermal phosphidation of various Co3O4nanostructures, with the aim of their application in asymmetric supercapacitors. Structural, morphological, elemental, surface area, and pore size analyses were conducted to understand the effects of annealing on the different Co3O4nanostructures during the formation of CoP nanoparticles. The results revealed that phosphidation of the initially grown Co3O4cubical-shaped nanostructures led to the formation of CoP nanoparticles with high surface area and optimum pore size. Electrochemical characterization of the optimized CoP electrodes showed a high specific capacitance of 2633 Fg−1at a current density of 0.66 Ag−1in a 2 M KOH aqueous electrolyte. Regarding stability, the CoP electrodes exhibited excellent performance, retaining 95 % of their initial capacity after 5000 cycles at 100 mVsec−1. Moreover, an asymmetric device was developed using activated carbon as the negative electrode and the optimized CoP as the positive electrode. This asymmetric device demonstrated a specific capacitance of 100 Fg−1at a current density of 0.256 Ag−1. Remarkably, at the constant current density of 6.41 Ag−1the device exhibited outstanding cycling stability, retaining 83.3 % of its initial capacity over 10,000 cycles. Additionally, it achieved an energy density of 35.5 Wh kg−1at a power density of 205.1 W kg−1.

Phosphate compounds have sparked the scenario and emerged as new electrode materials for energy storage systems due to their high redox chemistry. However, these materials suffer from sluggish electrode kinetics and low utilization efficiency, resulting in subpar storage performance. Herein, we report a facile and cost-efficient chemical method for directly anchoring cobalt phosphate (Co2P2O7) nanodots onto multiwalled carbon nanotubes (MWCNT) to design a multifaceted Co2P2O7/MWCNT core–shell-type structure. The as-designed heterostructure with dual charge storage profiles provides a high level of intercomponent synergy, promoting the occurrence of extrinsic pseudocapacitance. By ensuring continuous charge transfer pathways for sustained electrochemical performance, MWCNT support excellent electronic conductivity with good resilience to the dependability of Co2P2O7, resulting in exceptional mechanical robustness. The Co2P2O7/MWCNT exhibits significantly improved specific capacity and rate performance, outperforming pristine MWCNT. The assembled flexible all-solid-state symmetric supercapacitor device with a Co2P2O7/MWCNT electrode and a freestanding PVA-KOH electrolyte membrane possesses an exceptional specific energy of 57.3 W h kg–1with good power output. Moreover, as a result of the well-interwoven all-solid-state assembly, the device displays commendable cyclic stability with a retention of 105% even at 5000 cycles, along with good deformable compatibility. The lighting up of 21 red light-emitting diodes provides practical evidence for the as-fabricated device’s applicability in current miniaturized electronics.

Photoelectrochemical water splitting is of great attention due to its environmental friendly generation of clean fuels. Hematite (a-Fe2O3) is considered one of the promising candidates due to its intrinsic properties for the high performance photoelectrochemical electrode such as favourable bandgap (2.0-2.2 eV), a suitable energy band position, non-toxicity, low cost, and excellent chemical stability. Herein, we report about Sn-doped hematite nanorods and their implementation as photoanodes for photoelectrochemical water splitting. We provide the simple but efficient route to incorporate the Sn into the hematite without structural damage in the nanostructure and scrutinize the effect of Sn dopant on the photoelectrochemical activity of the hematite. By the two-step heat-treatment process, Sn can be successfully incorporated into the hematite, which reveals the enhanced photoelectrochemical responses compared with undoped hematite. We elaborate the effect of Sn dopant in the hematite on the photoelectrochemical activities, thereby the optimum concentration of Sn dopant can be suggested. In addition, the catalyst layer of the cobalt phosphate is introduced to further increase the photoelectrochemical performance of Sn-doped hematite nanorods.

Nanoscale architecturing of photoanodes with the improved photoelectrochemical activities for water splitting has been demonstrated by introduction of gold (Au) and reduced graphene oxide (rGO) to cadmium-sulfide (CdS). We optimized CdS thin film by an inert atmosphere heat-treatment, on which Au-rGO-coated CdS (Au-rGO@CdS) could be obtained by sequential deposition of rGO and Au. The morphology, structure and optical and vibrational properties of the CdS and Au-rGO@CdS samples were found to be in good correlation with the photoelectrochemical analysis. The Au-rGO@CdS thin film showed a current density of 5 mA/cm2 at 0 V (vs SCE), which is approximately 3.5 times higher than that of the as-prepared CdS thin film. The enhancement mechanism has been discussed elaborately through the extensive photoelectrochemical characterization.

Various compounds that are emerging contaminants pose a significant risk to aquatic ecosystems and human health due to their potential to harm human health and the environment.Thus, there is an urgent requirement to use effective remediation methods and techniques to minimize the harmful impact of these contaminants on the environment. Biochar (BC) is a lightweight black residue that is made of carbon after the pyrolysis of biomass. BC is a product that is stable, rich in carbon, and exhibited improved properties. BC has come up with fascinating properties and results to remediate these pollutants from the soil effectively. Furthermore, it becomes possible to recover resources using BC because of the benefits such as (a) it offers in terms of cost, (b) the preservation of nutrients, and (c) the efficiency with which it absorbs pollutants. Consequently, it is necessary to have a knowledge of the interaction involving biochar and resource recovery to explore the applicability of BC in the cleaning up of the surroundings and the exploitation of wastewater. This review emphasize the physio-chemical and biological modification methods for the preparation of various types of engineered BC. Therefore, the present review aims: (i) provide an overview of emerging pollutants of human activities in soil (ii) synthesis and engineer BC for field application (iii) critically discuss and evaluate the factors affecting large-scale application techno-economic challenges. The review provided insight into the areas that need immediate attention in the upcoming investigation regarding the use of engineered biochar for wastewater treatment.

Flexible solid-state supercapacitors embedded the fast charge rate of electric double-layer capacitive materials with high capacity pseudocapacitive type materials to exhibit better storage capacity and cycle life, hold great potential for portable microelectronic devices in the present days. Herein, we propose analogues state of art through the facile solution synthesis of multi-walled carbon nanotubes decorated by Ni3P2O8nanodots (Ni3P2O8/MWCNT) on a flexible substrate for supercapacitor application. Designed composite benefits from inter component synergistic effects wherein redox-enriched Ni3P2O8nanodots contribute 26- fold high-performance energy storage capability with reference to bare MWCNT, while MWCNT acts as a one dimensional conductive as well as mechanical support for Ni3P2O8growth. The corresponding flexible all-solid-sate symmetric supercapacitor designed from carboxymethyl cellulose-Na2SO4(CMC-Na2SO4) neutral gel electrolyte holds a maximum specific energy of 72.3 Wh kg−1with a power density of 6.4 kW kg−1across an extended voltage window of 1.8 V. In addition, the device's excellent deformation tolerance (103 % at mechanical bending of 170o) indicates promising potential for enhanced flexible energy storage.

Hybrid lead halide perovskites possess highly attractive optoelectronic properties that make them suitable for high-performance, self-powered photodetectors. Chemical vapor deposition (CVD) allows the large-area fabrication of high-quality polycrystalline perovskite thin films with large grain size, hence highly attractive as the active layer for self-powered photodetectors. In this study, CVD-deposited perovskite films were employed to realize high-performance sandwich-type photodetectors responsive in the visible range. In self-powered mode, these devices delivered a responsivity as high as 112 A/W, a specific detectivity of 3.5 × 1014Jones and an external quantum efficiency of 22,042% under red light. Further, these devices exhibited good moisture stability and negligible photoresponse degradation after 2160 h in ambient conditions. The long-term stability of their photoresponse was additionally demonstrated under UV (λ = 365 nm) illumination at 1 mW/cm2for 500 h. Our CVD-deposited perovskite films offer a promising avenue for the realization of high-performance, self-powered photodetectors with good operating stability for next-generation optoelectronic systems and their applications.

Nanoscale architecturing of photoanodes with the improved photoelectrochemical activities for water splitting has been demonstrated by introduction of gold (Au) and reduced graphene oxide (rGO) to cadmium-sulfide (CdS). We optimized CdS thin film by an inert atmosphere heat-treatment, on which Au-rGO-coated CdS (Au-rGO@CdS) could be obtained by sequential deposition of rGO and Au. The morphology, structure and optical and vibrational properties of the CdS and Au-rGO@CdS samples were found to be in good correlation with the photoelectrochemical analysis. The Au-rGO@CdS thin film showed a current density of 5 mA/cm2at 0 V (vs SCE), which is approximately 3.5 times higher than that of the as-prepared CdS thin film. The enhancement mechanism has been discussed elaborately through the extensive photoelectrochemical characterization.

Photoelectrochemical water splitting is of great attention due to its environmental friendly generation of clean fuels. Hematite (α-Fe2O3) is considered one of the promising candidates due to its intrinsic properties for the high performance photoelectrochemical electrode such as favourable bandgap (2.0–2.2 eV), a suitable energy band position, non-toxicity, low cost, and excellent chemical stability. Herein, we report about Sn-doped hematite nanorods and their implementation as photoanodes for photoelectrochemical water splitting. We provide the simple but efficient route to incorporate the Sn into the hematite without structural damage in the nanostructure and scrutinize the effect of Sn dopant on the photoelectrochemical activity of the hematite. By the two-step heat-treatment process, Sn can be successfully incorporated into the hematite, which reveals the enhanced photoelectrochemical responses compared with undoped hematite. We elaborate the effect of Sn dopant in the hematite on the photoelectrochemical activities, thereby the optimum concentration of Sn dopant can be suggested. In addition, the catalyst layer of the cobalt phosphate is introduced to further increase the photoelectrochemical performance of Sn-doped hematite nanorods.