Central Electro Chemical Research Institute is one of a chain of forty national laboratories under the aegis of the Council of Scientific and Industrial Research (CSIR) in New Delhi. Founded on 25 July 1948 at Karaikudi in Tamil Nadu, CECRI came into existence on the January 1953.
The drive for sustainable hydrogen production via water electrolysis demands the convergence of advanced electrocatalysts with systematically engineered electrochemical systems. This review critically examines the progression of electrochemical and photoelectrochemical (PEC) water-splitting technologies, emphasizing the transition from conventional coupled systems such as Alkaline water electrolysis (AWE), Proton Exchange Membrane (PEM), Anion Exchange Membrane (AEM), and PEC cells to emerging decoupled architectures incorporating redox mediators and solar integration. While coupled systems have advanced through innovations in catalyst design, zero-gap configurations, and modular stacks, they face scalability challenges due to gas crossover, stoichiometric imbalance in H2/O2 generation, and limited adaptability to intermittent renewables. To overcome these constraints, decoupled platforms utilizing reversible redox mediators, both liquid-phase and solid-state, offer spatial or temporal separation of HER and OER, enabling safer, membrane-free operation and enhanced system flexibility. This review comprehensively assesses engineering advancements across such architectures, including redox flow cells, solid-state mediator systems, wireless bipolar assemblies, and roll-to-roll shuttling designs. Integration of photovoltaics for unassisted, bias-free solar water splitting is also explored. From a system integration and reaction engineering standpoint, key strategies are discussed to optimize charge transfer kinetics, suppress parasitic side reactions, minimize gas crossover, and enhance long-term operational stability. By unifying insights across materials science, reactor architecture, and process intensification, this review outlines a roadmap for scalable, efficient, and grid-compatible hydrogen production technologies.
The rising demand for sustainable and scalable energy storage systems has positioned sodium-ion batteries (SIBs) as promising alternatives to lithium-ion batteries (LIBs) due to the Earth's abundance, low cost, and favourable redox potential of sodium. However, sodium has an intrinsically larger ionic radius than lithium and sluggish diffusion kinetics, posing significant limitations, including severe volume fluctuations and poor long-term cyclability in conventional electrode chemistries. This review provides a critical analysis of the advanced porous frameworks, including metal-organic frameworks (MOFs), covalent organic frameworks (COFs), porous organic polymers (POPs), porous organic hybrids (POHs), and transition metal chalcogenides (TMCs), that have emerged as compelling solutions to overcome these intrinsic drawbacks. These porous systems provide highly tunable architectures with controllable porosity, chemical functionality, and abundant active sites, offering a promising platform for achieving high specific capacity, enhanced ion transport, and mechanical accommodation of volumetric changes. A discussion is also presented on their structural merits, electrochemical performances and synthesis strategies, along with a comparison of their limitations and challenges. Finally, emerging approaches such as creation of hierarchical porosity, vacancy engineering and solid-state integration are highlighted as pathways to enhance the performance and guide the development of next-generation sodium-based energy storage systems.
In this work, a multi-metallic CoFeZn-MOF derived nanoporous carbon (CFZ-NPC) was synthesized, which exhibits excellent bifunctional oxygen electrocatalytic activity for both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). The catalyst demonstrates high ORR activity, with a half-wave potential of 0.81 V vs. RHE, and an OER overpotential of 0.379 V at 10 mA cm(-2). Moreover, the catalyst shows excellent operational stability over similar to 10 h. CFZ-NPC was further employed as an air cathode in rechargeable zinc-air batteries and benchmarked against commercial Pt/C + IrO2 catalysts. The binder-free CFZ-NPC air electrode, when used in a zinc-air battery, delivered a high open-circuit voltage of similar to 1.49 V and a low voltage gap of 0.70 V at 5 mA cm(-2). The MOF-derived catalyst exhibited excellent cycling stability over more than 800 cycles (5 min per charge/discharge) with minimal efficiency loss. Additionally, the battery achieved a high discharge specific capacity of similar to 991 mAh g([Zn])(-1) at a current density of 5 mA cm(-2).
The growing demand of inhibitors for the prevention of corrosion leads to the search of sustainable and ecofriendly inhibitors. This study deals with the corrosion protection of mild steel using alkaloid extract of Berberis asiatica stem in 1 M H2SO4. The Ultraviolet-Visible (UV-Vis) and Fourier transform infrared (FTIR) spectroscopy established the presence of compounds containing nitrogen and oxygen. Strong coordination between the inhibitor molecules and the metal surfaces has been established by the clear identification of N1s and O1s peaks in X-ray photoelectron spectroscopy (XPS), corresponding to Fe-N and Fe-O bonds, respectively. Gravimetric and electrochemical methods were used to study IE. The results showed that IE increased with increasing inhibitor concentration, achieving 93.34 % IE at a concentration of 10 ppm. Inhibition efficiency decreases with increasing immersion duration or temperature. The inhibiting mechanism is believed to result from the adsorption of the alkaloid molecules at the MS-solution interface, following Langmuir-type behavior and indicating a single-layer (monolayer) adsorption process. The standard free energy of adsorption, Delta G degrees =-41.20 kJ mol-1, and activation energy (Ea) up to 97.94 kJ mol-1 were determined. Thermodynamic calculations confirmed that the adsorption is spontaneous and endothermic. The kinetic calculation confirmed that charge-transfer reactions are the rate-controlling step in corrosion. Field emission scanning electron microscopy (FE-SEM) and Atomic force microscopy (AFM) revealed smoother surfaces in the inhibited samples. This clearly reflects that Berberis asiatica's alkaloids act as a promising, environmentally benign, and excellent green corrosion inhibitor for mild steel in acidic environments.
Strong bifunctional electrocatalysts capable of sustaining both oxygen reduction (ORR) and oxygen evolution (OER) at high depths-of-discharge are crucial for practical rechargeable zinc-air batteries (ZABs). Here, we present a novel MnFeCoNiCu high-entropy alloy uniformly anchored on nitrogen-doped carbon nanotubes, derived from a high-entropy layered double hydroxide precursor. A dicyandiamide-assisted pyrolysis enabled simultaneous CNT growth, nitrogen doping, and alloy nanoparticle formation, yielding a single-phase face-centered cubic HEA at 900°C (HEA 900). Structural analyses confirmed homogeneous atomic-level metal dispersion, significant lattice distortion, and strong metal-carbon coupling, providing abundant active sites and enhanced conductivity. Owing to these synergistic effects, HEA 900 exhibited excellent bifunctional activity with an OER overpotential of 475 mV at 10 mA/cm2, an ORR half-wave potential of 0.81 V, and a low ΔE of 0.89 V. The HEA-based ZAB showed a near-theoretical specific capacity of 801 mAh/gZn, and a peak power density of 186 mW/cm2. The cell's remarkable reversibility and mechanical robustness were confirmed by extended cycling under high DOD (up to 10 h per cycle) and impressive energy efficiency over 3325 cycles. Flexible gel-polymer ZABs further demonstrated robust mechanical and electrochemical durability, highlighting this HELDH-derived HEA strategy as a promising paradigm for entropy-engineered catalysts in high-performance ZABs.
