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Due to the future uses of solar energy in different areas, such as the oxidation of fossil fuel-based contaminants, the reduction of carbon dioxide, heterogeneous photocatalysis, and the generation of inexhaustible and renewable hydrogen gas exploits semiconductors. As a metal free photocatalyst, graphitic carbon nitride (g-C 3 N 4) is classified to solve these energy hazards and ecological difficulties owing to its excellent electronic structure with band energy of about 2.7 eV, robust photochemical stability, and better light-harvesting efficiency. However, its photocatalytic performance is still insufficient due to a minor surface area and poor conductivity. Therefore, heterojunction formation by combining it with a giant band gap material is a potential approach to reestablish polarization in its distinctive band structure, increase its light absorption capacity and enhance its surface area. In this regard, various synthesis techniques have been applied so far to integrate g-C 3 N 4 and other materials for boosting its photocatalytic activity. So far, metal oxide, sulfides, and ferrites are three crucial groups of materials that have been identified and defined to be used to synthesize g-C 3 N 4 dependent nanocomposites. As a result, in this review, we have compiled a list of the most recent g-C 3 N 4 nanocomposites with their applications in solar energy adaptation and pollution control. This study concludes an overview about the next steps to study the nanomaterials based g-C 3 N 4 composites and a range of additional insights to solve the present problems. • This review addresses the properties and structures of g-C 3 N 4 photocatalyst structure. • Pros and cons of their synthesis techniques. • The types of the g-C 3 N 4 -based nanocomposite are emphasized. • Approaches to improve the photocatalytic activity of g-C 3 N 4. • The most up-to-date photocatalytic applications were thoroughly discussed. [ABSTRACT FROM AUTHOR]

The escalating need for energy in the context of future development has prompted a significant surge in research efforts focused on exploring renewable energy sources. The utilization of transition metal oxides in conjunction with reduced graphene oxide (rGO) as economically viable electrocatalytic materials for the oxygen evaluation reaction (OER). This study showcases a straightforward hydrothermal technique to produce perovskite-type ZnMnO 3 nanoparticles that interact with reduced graphene oxide (rGO) to examine electrocatalytic efficiency of ZnMnO 3 /rGO catalyst, particularly in relation to OER. However, electrochemical results of the ZnMnO 3 /rGO catalyst exhibited outstanding electrocatalytic performances with significant overpotential (η) of 253 mV at 10 mA cm−2. Additionally, it exhibited Tafel slope of 38 mV dec−1, indicating efficient catalytic activity. Furthermore, the synthesized catalyst demonstrated a significantly low impedance (R ct) of 1.91 Ω with higher stability after the 5000th cycle. The catalytic electrode shows excellent long-term stability for OER, making it a promising alternative to electrocatalysts for new-generation applications. [Display omitted] • Fabrication of ZnMnO 3 /rGO catalyst was involved for enhanced OER activity. • ZnMnO 3 /rGO catalyst shows a reduced overpotential (253 mV). • ZnMnO 3 /rGO demonstrates cycling stability of 30 h even after 5000th cycle. • ZnMnO 3 /rGO catalyst reveals reduced charge transfer resistance (R ct) of 0.65 Ω. [ABSTRACT FROM AUTHOR]

Significant research is currently performed on electrochemical water splitting to solve ecological problems and energy issues. Sustainable and eco-friendly energy systems prefer to generate cost-effective electrocatalyst material with higher stability and excellent electrocatalytic activity to speed up the oxygen evolution reaction (OER) process. The current study followed a hydrothermal approach to develop a barium cerium oxide nanohybrid with g-CN (BaCeO 3 /g-CN) as an electro-catalyst for an efficient OER process in 1.0 M KOH. Physical characteristics analyses confirmed the enhanced activity of the synthesized BaCeO 3 (BCO) and BCO/g-CN nanohybrid materials. The evaluated increased performance may be ascribed to improved morphological characteristics and substantial surface area (212 m2 g−1). The nanocomposite as mentioned above (BCO/g-CN) exhibits significant potential for effective OER in electrochemical assessments due to its abundant active spots and accelerated charge transfer process. Further, the electro-catalytic activity of the composite is improved, as demonstrated by a reduced overpotential (η = 210 mV) with Tafel value (36 mV dec−1) in comparison to pristine BCO (η = 262 mV and 52 mV dec−1) for OER. The material exhibited a reduced charge transfer impedance (R ct = 0.7 Ω), confirmed by EIS analysis. It also demonstrated a substantial ECSA (electrochemical active surface area) of 237.5 cm2 as compared to the pure BCO (137.5 cm2) material. Moreover, electrocatalyst material durability for 30 h was assessed by a chronoamperometric study. Thus, BCO/g-CN exhibits a notable rise in electrochemical properties, suggesting that it is a viable candidate for prospective OER applications. [Display omitted] • BaCeO 3 /g-CN nanomaterial was synthesized by simple hydrothermal technique. • The conductivity of nanohybrid BaCeO 3 was analyzed under 1.0 M KOH for OER. • BaCeO 3 /g-CN material had higher surface area (70.6 m2 g−1) than pure BaCeO 3. • The cyclic stability of BaCeO 3 /g-CN is remarkable after 5000 cycles. [ABSTRACT FROM AUTHOR]

We confirmed a specific copolymerization (molecular doping) method for the covalent integration of 2,4-dihydroxyoxazole (DHO) monomer within the framework of carbon nitride (CN). The obtained composites xCN/DHO reveal a sophisticated dual-phase photocatalytic activity, which can effectively reduce and oxidize the CO 2 and NO 2 sources in an aqueous solution and simultaneously performed the oxidation of olefin (C C) in an organic state. This momentous dual state activity is concerned with the lipophilicity elevation from the convolution of oxazole (DHO) monomer within the shell of CN semiconductor. This modulation demonstrates the probability of hydrophobic olefin molecules, escorted in the bulk of CN and associated with the oxidation of hydroxyl radicals (∗OH) caused by photogenerated electrons/holes. In this approach, the olefinic compound allusively consumes the photoinduced electrons/holes through elevated CN/DHO, thus stimulating the entire photocatalytic route. Recent research provides a novel strategy for the production of solar fuels upon organic synthesis via the oxidizing capacity of photoinduced holes within free semiconductors of amphiphilic metals. Likewise, the results of the NO 2 photocatalytic reaction demonstrated that molecular doping drastically reduces the oxidative capacity and improves its reducing propensity. More importantly, the CO 2 reduction process supervenes into an extreme aggregation of methane (CH 4) as well as carbon monoxide (CO) in the presence of co-catalyst Pt respectively. The photocatalytic results demonstrate that the copolymerized CN provide the greatest reduction/oxidation potential, which is due to its chemical oxidation phase that causes superior fluctuations in whole performance under solar irradiation. • Synthesis of oxazole (DHO) based carbon nitride (CN) through molecular engineering. • Samples were utilized for photocatalytic CO 2 reduction and NO 2 oxidation. • The momentous activity is concerned towards the convolution of DHO within CN. • Samples alter the probability for hydrophobic olefin molecules due to *OH radicals. • The reduction/oxidation process happen due to excess of electrons/holes in materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Recently, the graphite based heterogeneous photocatalysts has attained tremendous research attention in various environmental applications. Among them, the graphitic carbon nitride (g-C 3 N 4) is categorized as a unique solar active particle with its outstanding intrinsic properties i.e., adequate band configuration, excellent light absorptivity and thermo-physical durability, which make it highly useful and reliable for revenue transformation and ecological concerns. Considering the intrinsic potential of g-C 3 N 4 in photocatalysis, so far, no report has been done in literature for its extraordinary configuration, morphological characteristics and perspective tuning for said applications. To overcome this research gap, our primary emphasis of this review regarding photocatalysis is to provide layout as well as the advancement of visible-light-fueled materials as highly stabilized and extremely effective ones for pragmatic implementation. Thus, this existing comprehensive assessment conducts a systematic survey over visible light driven non-metal novel g-C 3 N 4. The major advancement of this evaluation is the fabrication of well-designed nanosized g-C 3 N 4 photocatalysts with unique configurable frameworks and compositions. Furthermore, alternative techniques in order to customize the analogue band configuration and noticeable cultivation such as metal (cation), nonmetal (anion) doping, worthy metal activating, and alloy initiation with certain semiconductors are discussed in detail. In addition to this, g-C 3 N 4 photocatalytic functionalities towards photocatalytic hydrogen evolution, CO 2 photoreduction, biological metal ions deterioration as well as bacterial sanitization are also presented and discussed in detail. Therefore, we believe that such a pivotal compact assessment can provide a roadmap in several perspectives on the currently underway obstacles in the innovation of effective g-C 3 N 4 catalytic design processes. Moreover, this critical assessment will ultimately serve as a useful supplement in the research area of g-C 3 N 4 nanosized photocatalysts and for the researchers working on its key aspects in diverse range of natural, chemistry, engineering and environmental applications. • Graphitic carbon nitride (g-C 3 N 4) is a metal-free sustainable photocatalyst with a band gap of 2.7 eV. • G-C 3 N 4 has improved light absorption performance as well as electronic features. • Multiple synthetic approaches are being used with g-C 3 N 4 to improve its photocatalytic capabilities. • Metals/nonmetals doping, activation, and alloy formation are employed for g-C 3 N 4 nanocomposites. • Our review includes the latest current g-C 3 N 4 nanocomposites and their photocatalytic implications. [ABSTRACT FROM AUTHOR]

Recently, the graphite based heterogeneous photocatalysts has attained tremendous research attention in various environmental applications. Among them, the graphitic carbon nitride (g-C 3 N 4) is categorized as a unique solar active particle with its outstanding intrinsic properties i.e., adequate band configuration, excellent light absorptivity and thermo-physical durability, which make it highly useful and reliable for revenue transformation and ecological concerns. Considering the intrinsic potential of g-C 3 N 4 in photocatalysis, so far, no report has been done in literature for its extraordinary configuration, morphological characteristics and perspective tuning for said applications. To overcome this research gap, our primary emphasis of this review regarding photocatalysis is to provide layout as well as the advancement of visible-light-fueled materials as highly stabilized and extremely effective ones for pragmatic implementation. Thus, this existing comprehensive assessment conducts a systematic survey over visible light driven non-metal novel g-C 3 N 4. The major advancement of this evaluation is the fabrication of well-designed nanosized g-C 3 N 4 photocatalysts with unique configurable frameworks and compositions. Furthermore, alternative techniques in order to customize the analogue band configuration and noticeable cultivation such as metal (cation), nonmetal (anion) doping, worthy metal activating, and alloy initiation with certain semiconductors are discussed in detail. In addition to this, g-C 3 N 4 photocatalytic functionalities towards photocatalytic hydrogen evolution, CO 2 photoreduction, biological metal ions deterioration as well as bacterial sanitization are also presented and discussed in detail. Therefore, we believe that such a pivotal compact assessment can provide a roadmap in several perspectives on the currently underway obstacles in the innovation of effective g-C 3 N 4 catalytic design processes. Moreover, this critical assessment will ultimately serve as a useful supplement in the research area of g-C 3 N 4 nanosized photocatalysts and for the researchers working on its key aspects in diverse range of natural, chemistry, engineering and environmental applications. • Graphitic carbon nitride (g-C 3 N 4) is a metal-free sustainable photocatalyst with a band gap of 2.7 eV. • G-C 3 N 4 has improved light absorption performance as well as electronic features. • Multiple synthetic approaches are being used with g-C 3 N 4 to improve its photocatalytic capabilities. • Metals/nonmetals doping, activation, and alloy formation are employed for g-C 3 N 4 nanocomposites. • Our review includes the latest current g-C 3 N 4 nanocomposites and their photocatalytic implications. [ABSTRACT FROM AUTHOR]

Excessive reliance on fossil fuels causes a variety of difficulties and the use of efficient electrocatalysts material has exhibited significant attention for high electrocatalytic activity. Most transition metal oxide materials performance can be enhanced by the incorporation of metals for OER activity. This work presents the synthesis of samarium (Sm) doped silver niobium oxide (AgNbO 3) was achieved using sonication techniques. An electrocatalyst, Sm-doped AgNbO 3 , has shown promising results for oxygen evolution reaction (OER) in alkaline medium with a significant increase in active sites, enhanced electrical conductivity and improved stability. The Sm-doped AgNbO 3 electrocatalyst exhibits overpotential of 203 mV and Tafel slope of 35.22 mV dec−1 for OER activity at current densities of 10 mA cm−2. By utilizing, electrochemical surface area (ECSA), the Sm-doped AgNbO 3 electrocatalyst exhibited higher ECSA values of 1009 cm−2 with a higher roughness factor of 2008.60. Further, observations of low charge transfer resistance value (R ct = 0.17 Ω) along with a durability of 50 h, indicate that this material is highly efficient and long-lasting as an electrocatalyst for energy conversion systems. [Display omitted] • The sonication technique was employed to synthesized Sm-doped AgNbO 3 electrocatalyst. • BET confirmed larger catalytic surface area of Sm-doped AgNbO 3 electrocatalyst was responsible for higher catalytic efficiency for OER. • Electrocatalytic consequences show Sm-doped AgNbO 3 electrocatalyst exhibits the lower Tafel slope (35.22 mV dec−1) with overpotential 203 mV at current density of 10 mA cm−2. • Sm-doped AgNbO 3 electrocatalyst shows the higher stability for 50 h. • Sm-doped AgNbO 3 electrocatalyst exhibited conductive nature with lower value of R s (0.65 Ω) and R ct (0.17 Ω). [ABSTRACT FROM AUTHOR]

In light of environmental problems such as the depletion of hydrocarbon resources and global warming, the use of environment-friendly power production has become crucial nowadays. Hydrogen can serve as a globally friendly energy source because the byproduct of hydrogen combustion is only water. By a hydrothermal approach, we synthesized barium manganese oxide (BaMnO 3) embedded on reduced graphene oxide (rGO) as a competent electrocatalyst for OER. We utilized X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive x-rays (EDX), Brunauer Emmette Teller (BET) and Raman to determine the crystal structure, morphology, elemental composition, surface area and lattice phenomena of the fabricated rGO/BaMnO 3 nanocomposite. The BaMnO 3 agglomerated nanoparticles were incorporated into the mesoporous hollow carbon nanosheets to form amorphous textured embedded rGO/BaMnO 3. This enhanced the intrinsic reactivity of rGO/BaMnO 3 nanocomposite for the oxygen evolution reaction (OER) in addition to increasing the effective surface area of the electrolyte. The electrochemical outcomes demonstrate that synthesized nanocomposite exhibited an impressive Tafel slope (36 mV dec−1), lowest overpotential (202 mV) and remarkable stability over 35 h. Therefore, the fabricated nanocomposite displayed exceptional efficiency in OER process as well as for numerous other future applications. [Display omitted] • RGO/BaMnO 3 nanocomposite was fabricated via facile hydrothermal technique. • Various analytical techniques were conducted to evaluate the material's properties. • The developed material exhibit OER process, which can be initiated by applied electrocatalyst at 0.50 V vs RHE using 1.0 ssM KOH solution. • The rGO/BaMnO 3 nanocomposite exhibits the minimal overpotential (202 mV) with low Tafel slope (36 mV dec−1). • RGO decorated BaMnO 3 (rGO/BaMnO 3) exhibiting remarkable stability of 35 h tested via chronoamperometry. [ABSTRACT FROM AUTHOR]

Currently, the entire world is confronted with two major challenges such as a dearth of energy resources and a progressively deteriorating state of the environment. The significance of generating and storing ecologically sustainable energy has grown in prominence due to the depletion of non-renewable resources. Pseudocapacitors have attracted the attention of energy specialists because of their enhanced cyclic life and increased energy/power density. The current study involved the synthesis of ZnSe@FeSe nanocomposite by hydrothermal technique, with the aim of exploring its potential applications in supercapacitors. Multiple analytical approaches were used to examine the morphology, structure and texture of electrode material. Electrochemical experiments revealed that ZnSe@FeSe electrode showed a higher specific capacitance (C s) of 1419.8 F g−1, high energy density (E d) of 63.2 Wh kg−1, high power density (P d) of 283.2 W kg−1, and long cyclic stability over 5000th CV cycles as compared to ZnSe and FeSe electrodes in 2.0 M KOH. This study highlights the efficiency of ZnSe@FeSe nanocomposite developed by using the economic, environment friendly and efficient hydrothermal method, and it can also be used in future energy-related applications like fuel cells, photocatalysis and hydrogen evolution reactions (HER). • Hydrothermal synthesis of ZnSe@FeSe nanocomposite used as energy storage electrode material. • Investigation of the synergistic effect of binary transition metals with selenide nanocomposite for energy storage devices. • ZnSe@FeSe nanocomposite exhibited higher specific capacitance (C s) of 1419.8 F g−1 than individual metal chalcogenides. • The ZnSe@FeSe electrode showed exceptional cyclic stability for up to 5000th cycles of CV analysis. [ABSTRACT FROM AUTHOR]

In recent years, the most appealing way to harvest solar energy via cost-effective, renewable, clean and sustainable technology is the artificial photocatalysis which has drawn multidisciplinary attention to mitigate the upcoming energy disaster and environmental issues in the arena of sustainable development of society. For this purpose, significant progress has been made, regarding the selectivity of photocatalytic energy sources for potential productivity using solar energy pathway, nonetheless it has still become a difficult task for scientists in order to make and resolve the noteworthy problem of increasing global deterioration. According to a recent literature survey, the non-metal based graphitic carbon nitride (g-C 3 N 4) as a fascinating conjugated polymer based photocatalyst has emerged as a new research hotspot in the form of viable option related to its earth abundant elements, good stability, and ease in fabrication. Still, there are many disadvantages associated with g-C 3 N 4 , such as rapid recombination of photoexcited electron-hole pairs, which ultimately affect the photocatalytic hydrogen (H 2) and carbon dioxide (CO 2) conversion under solar illumination. Previously published several reviews only emphasize the proficient use of g-C 3 N 4 photocatalyst for overall sustainable energy production as an effective treatment strategy. But the literature has never been addressed the use of g-C 3 N 4 with different morphological and structural characteristics for simultaneous H 2 production and carbon dioxide reduction. Therefore, the proper designing and development of novel photocatalysts with proper surface tuning and intrinsic properties towards efficient energy harvesting is of utmost interest. This review article is basically designed to properly address the existing issues and the recent progress of g-C 3 N 4 through various strategies with the aim of obtaining a robust and resourceful photocatalyst towards sustainable energy production. In this context, we had a clear debate regarding the proper tuning of g-C 3 N 4 based photocatalysts through various fabrication strategies, such as electronic structure via metals/non-metals doping, defects engineering, carbon dots, etc. along with Z-scheme heterojunctions, bimetallic cocatalyst, and organic metal-organic framework. At the end, this review is devoted to sufficiently summarizing the recent advancements and the possible future recommendation of the fundamental contribution of g-C 3 N 4 in a wide variety of sustainable energy production fields. [Display omitted] Scheme. Proposed graphical illuatration defining the overveiw of this manuscript. • The photocatalytic main principles of g-C 3 N 4 were comprehensively evaluated. • The key functional characteristics of g-C 3 N 4 photocatalysts were acknowledged. • The various architectural practices for g-C 3 N 4 photocatalysts were described. • The key characteristics of novel g–C 3 N 4 –based composites were outlined. • Significant photocatalytic functionalities of g-C 3 N 4 were discussed in detail. [ABSTRACT FROM AUTHOR]

Solvothermal Bi 2 MoO 6 hierarchical microflowers synthesis has been successfully attempted. Methanol, ethanol and isopropanol have been mediated to synthesize three kinds of Bi 2 MoO 6 hierarchical microflowers. Highly oriented (311) plane growth of orthorhombic Bi 2 MoO 6 hierarchical microflowers have been confirmed. Interstitial vacancies and its role on electrochemical activity have been extensively discussed. Electrode fabrication was constructively done by using Ni foam substrate. Half cell arrangement of each electrode in alkaline medium has been designed to measure the electrochemical activity towards water oxidation. High current density of 356 mA/cm2 was afforded by Bi 2 MoO 6 hierarchical microflowers mediated by ethanol solvent during synthesis. Low Tafel slope value of 43 mV/dec has been reported to obtain 10 mA/cm2 current density. Higher conductivity long with very good electron transportation has been achieved and is also adapted for 12 h long time stability test and achieved 86% of retention in its performance. Hence, optimally prepared Bi 2 MoO 6 hierarchical microflowers could be an efficient electrode for clean energy fabrication. • Bi 2 MoO 6 revealed high 356 mA/cm2 current density in OER activity. • Bi 2 MoO 6 revealed low 43 mV/dec overpotential to obtain 10mA/cm2. • Achieved higher conductivity with good electron transportation. • Bi 2 MoO 6 electrode achieved 12 h long time stability of 86% retention. [ABSTRACT FROM AUTHOR]

In this study, nickel cobalt oxide (NiCo 2 O 4) microspheres were prepared by using facile hydrothermal route. The structural confirmation of bimetal oxide formation was acquired by X-ray powder diffraction and Raman studies. The formation of microspheres combined via irregular nanosheets was confirmed by scanning electron microscopy. Highly oriented NiCo 2 O 4 microspheres yielded a high current density (258 mA/g) at 10 mV/s and low overpotential (224 V). The highly active electrode showed efficient electron transportation towards oxygen evolution reaction. Long-term stability over 16 h was achieved by the fabricated high-performance NiCo 2 O 4 electrode. It is recommended that NiCo 2 O 4 microspheres obtained from 3:1 stoichiometry ratio of Ni and Co would lead to new electrocatalysts that give best performance than expensive catalysts used currently in the water oxidation process. • NiCo 2 O 4 is synthesized by hydrothermal with different ratios of Ni:Co. • NiCo 2 O 4 yields high 258 mA/g current density at 10 mV/s. • NiCo 2 O 4 revealed low 224 V overpotential. • NiCo 2 O 4 showed efficient electron transportation towards oxygen evolution. • Long time stability over 16 h has been achieved. [ABSTRACT FROM AUTHOR]