Water splitting using renewable energy resources is an economic and green approach that is immensely enviable for the production of high-purity hydrogen fuel to resolve the currently alarming energy and environmental crisis. One of the effective routes to produce green fuel with the help of an integrated solar system is to develop a cost-effective, robust, and bifunctional electrocatalyst by complete water splitting. Herein, we report a superhydrophilic layered leaflike Sn4P3 on a graphene–carbon nanotube matrix which shows outstanding electrochemical performance in terms of low overpotential (hydrogen evolution reaction (HER), 62 mV@10 mA/cm2, and oxygen evolution reaction (OER), 169 mV@20 mA/cm2). The outstanding stability of HER at least for 15 days at a high applied current density of 400 mA/cm2 with a minimum loss of potential (1%) in acid medium infers its potential compatibility toward the industrial sector. Theoretical calculations indicate that the decoration of Sn4P3 on carbon nanotubes modulates the electronic structure by creating a higher density of state near Fermi energy. The catalyst also reveals an admirable overall water splitting performance by generating a low cell voltage of 1.482 V@10 mA/cm2 with a stability of at least 65 h without obvious degradation of potential in 1 M KOH. It exhibited unassisted solar energy-driven water splitting when coupled with a silicon solar cell by extracting a high stable photocurrent density of 8.89 mA/cm2 at least for 90 h with 100% retention that demonstrates a high solar-to-hydrogen conversion efficiency of ∼10.82%. The catalyst unveils a footprint for pure renewable fuel production toward carbon-free future green energy innovation.

In energy storage-device it is highly crucial to develop durable electrode materials having high specific capacitance and superior energy density without disturbing its inherent flexibility. Herein, we demonstrate three-dimensional graphene oxide decorated monodispersed hollow urchin γ-MnS (γ-MnS@3DG) via proficient one-step solvothermal method. The designed material delivers a remarkable capacitance of 858 F g −1 at 1 A g −1 . A flexible solid state asymmetric supercapacitor (ASCs) device assembled using surface activated carbon cloth (CC) decorated with γ-MnS@3DG as positive and three-dimension graphene on carbon cloth (3DG@CC) as negative electrode, (γ-MnS@3DG//3DG). The device delivers 26 Wh kg −1 energy density at power density 500 W kg −1 @ 1A g −1 and retains favorable energy density 17.8 Wh kg −1 at an ultrahigh power density of 1500 W kg −1 @3 A g −1 . This carbon embedded transition-metal sulfide (TMS) based ASC demonstrates eminent mechanical flexibility under rigorous bending states maintaining invariant performance.

To address the need for renewable-energy technology for the growing population, environmentally benign hydrogen fuel generation via water splitting has become a game-changer that can replace fossil fuels. Herein, we report superhydrophilic selenium-anchored nickel phosphide (Ni5P4) on the surface of a low-cost, highly porous melamine foam-graphene-carbon nanotube matrix via the facile solvothermal method. The developed electrocatalyst renders superior electrocatalytic performance with long-term durability for minimum 10 days at a high current density of 300 mA/cm2 with a small deviation of 2%, allowing the commercialization of the catalyst toward industrial-grade application. The electrocatalytic performance is analyzed in terms of a low overpotential of 130 mV@10 mA/cm2 with a small Tafel slope of 98 mV/dec. Moreover, the as-designed catalyst has shown a remarkable performance in the smart utilization of waste heat into green fuel production. This work provides an insight into adopting a feasible strategy to develop a low-cost efficient electrocatalyst capable enough for the facile management of waste heat that could be an attractive paradigm of green fuel synthesis via renewable electrochemical energy conversion.

In an energy storage device, it is indeed a necessity to develop a flexible binder-free electrode. However, the rational design of such a binder-free electrode with high energy density and long cyclic stability is a great challenge for the scientific community. Herein, Se-anchored NiCoP nanoparticles have been developed that are in situ decorated on the surface of polyacrylonitrile-based heat-treated flexible carbon nanofibers (CNFs). The as-designed electrode demonstrates a remarkable specific capacitance/ capacity of 994 F g −1 /497 mAh g −1 at 1 A g −1 . The flexible solid-state symmetric supercapacitor (SSC) device delivers 76.86 Wh kg −1 energy density at a power density of 843.75 W kg −1 at 0.75 A g −1 and retains a promising energy density of 22.75 Wh kg −1 at an ultrahigh power density of 11250 W kg −1 at 10 A g −1 , respectively. The device also shows excellent long cyclic stability in terms of 94.12% capacitive retention along with 98.65% Coulombic efficiency after 15000 cycles at an applied high current density of 10 A g −1 . The synergetic effect of Se-anchored NiCoP with CNF along with the significant protection of NiCoP by a thin graphitic shell as well as suitable anchoring of electroactive materials on a CNF matrix via Se bridging may help to achieve such a high-performance energy storage device. The four sets of 1 × 1 cm 2 prototype devices (connected in series) are capable of enlightening a red-light-emitting diode (2.2 V) for 8 min and rotating a 3 V electric direct-current motor for 4 min via charging through a standard Si solar panel (6 V) illuminated by a 50 W street light for 2 min. The study creates an avenue toward the realistic drive of renewable energy conversion via the development of a high-performance flexible energy storage device.

Developing an efficient capacitive matrix along with the emergence of battery-type characteristics is the key priority function to attain high-performance asymmetric supercapacitors (ASCs). The rational design of metal-rich transition metal phosphides with a remarkable electrochemical activity and rich valence state possesses an efficient approach to overcome their limitation toward the low-rate capability with poor cycle life against metal deficient counterparts for their practical application. Herein, the metal-rich porous vanadium-doped nickel phosphide (V-Ni12P5) nanoflakes have been synthesized via a one-step solvothermal method. The as-synthesized electrode delivers a high specific capacity of 1455 F g–1 at a current density of 1 A g–1, and the corresponding assembled ASC device delivers a maximum energy density of 38.41 Wh kg–1 at a power density of 626.48 W kg–1 as well as long term cycling stability with 76.3% capacitive retention after 11,000 cycles. The assembled four sets of 1 × 1 cm2 devices in series designed with the help of a flexible carbon cloth matrix can light a red LED for 3 min and can rotate a 3 V home-designed windmill device for 1 min with in situ charging via a 6 V standard silicon solar panel illuminated by 50 W street light for 1 min. The flexible device can retain its invariant capacitive performance under rigorous twisting and bending at variable angles of 0, 90, and 135°. The significant enhancement (∼60%) of electrochemical activity for doped systems is mainly attributed to the generation of partial positive polarity on the metal centers and thereby induces strong adhesion of electrolytes under prolonged operation. Hence, this present work demonstrates the excellent capability of V-Ni12P5 nanoflakes toward the realistic drive of renewable energy conversion, unveiling the booming technology toward reliable high-performance hybrid energy-storage systems.