This research introduces and optimizes a novel multi-generation power system integrating a steam Rankine cycle (SRC), a gas turbine (GT), an absorption refrigeration cycle (ARC), a proton exchange membrane (PEM) electrolyzer, and a CO2 separation unit. This system is designed to improve energy efficiency while simultaneously capturing CO2 and producing hydrogen through electrolysis. Two configurations-with and without ARC-are evaluated using a genetic algorithm-based multi-objective optimization framework, which considers exergetic efficiency, CO2 emission reduction, and total cost rate. The findings demonstrate that the proposed system improves exergetic efficiency by up to 71% and reduces CO2 emissions by up to 3.9% compared to a standalone GT system. Furthermore, the system without ARC achieves higher hydrogen production, while the system with ARC provides valuable cooling. These findings demonstrate the feasibility and environmental advantages of integrated power, CO2 capture, and H 2 blending systems for sustainable energy generation.
The dry reforming of methane (DRM) offers a promising route for the simultaneous valorisation of CH4 and CO2 into syngas. However, practical implementation of Ni-based catalysts remains limited by carbon deposition and the restricted availability of catalytically active metallic Ni species. In this study, the effect of controlled strontium (Sr) promotion (1-3 wt.%) on a catalyst containing a fixed Ni loading of 5 wt.% supported on a MgOZrO2 mixed-oxide (MSZ) was systematically investigated to elucidate the role of Sr in modifying surface basicity and coke formation behaviour. Structural analysis revealed that Sr incorporation did not alter the bulk crystalline phases or porosity of the MSZ support. However, Sr significantly influenced the surface chemical properties of the catalyst, enhancing basicity and altering Ni reducibility at moderate loadings. The catalytic evaluation under DRM conditions at 700 degrees C (CH4/CO2/N2 = 3:3:1 and gas hourly space velocity (GHSV) = 42,000 mL g-1h-1) revealed that the catalyst with 1 wt.% Sr loading (5Ni-1Sr/MSZ) exhibited the most favourable performance, achieving 55.7% H2 yield, 68.3% CO yield and an H2/CO ratio of 0.83. Moreover, Sr promotion significantly improved resistance to carbon deposition compared to the unpromoted catalyst. Response surface methodology (RSM) applied to the optimal 5Ni-1Sr/MSZ catalyst identified a broad operating window with enhanced H2 yield, demonstrating the robustness of the optimized catalyst beyond single-point reaction conditions. These results highlight the beneficial role of Sr promotion in improving catalyst stability for DRM applications.
Hydrogen is a promising clean, renewable energy source with zero carbon waste, generated via an electrochemical conversion system. The key to electrocatalytic water splitting lies in the semi-reactions, such as OER/ HER, and overall water splitting, yet remains hindered by their sluggish kinetics. To overcome this challenge, the development of an appropriate, competent, low-cost, and efficient bifunctional electrocatalyst for hydrogen and oxygen evolution is highly desirable. In this perspective, we adopted a hydrothermal method to design an efficient CeSe2-Cu2O/g-C3N4 heterostructure as a bifunctional electrocatalyst. The layered structure of roughly spherical nanoparticles and the higher redox potentials of Ce3+/Ce4+ and Cu1+/Cu2+ on the catalyst surface created heterojunction interfaces for active centres and strong electronic interactions for robust charge-transport rates, which accelerate the OER and HER activity with impressive electro-catalytic potential of 202 and 89 mV at standard current density by using 1.0 mol alkaline electrolyte. Besides, the anionic edge sites in the structure of CeSe2-Cu2O/g-C3N4 optimised the adsorption of reactants and intermediates, thereby demonstrating superior stability of 60 h and 80 h for OER and HER, respectively. In the overall water electrolysis test, the CeSe2-Cu2O/g-C3N4 electrolyser exhibits excellent stability for 40 h at 1.53 V, maintaining 10 mA cm-2. The present work proposes a new approach to designing an efficient and stable bifunctional catalyst to enhance electrocatalytic water splitting performance by coupling g-C3N4 via an anionic bimetallic strategy.
Fossil fuel reserves depletion necessitates the generation of sustainable energy through hydrogen from water splitting, with efforts focusing on optimizing bifunctional electrocatalysts for improved efficiency. In this study the Fe-doped (1%, 5%, 10%) CoCu2Se4 mesoporous nanosheet array on a Ni foam substrate with varying concentrations using a hydrothermal synthesis. Fe doping in CoCu2Se4 lattice results in structural distortions and electronic modifications. The study discloses the insights of Fe+3 doping in CoCu2Se4 lattice sites lead to electronic modulation, improve conduction and catalytic mechanisms. Fe+3 higher electronegativity facilitates electron redistribution, modulating the band structure and reducing charge recombination losses. The study found that the optimized 5% Fe-doped CoCu2Se4 electrode demonstrated exceptional OER performance with a 216 mV of low overpotential along with a minimal 69.65 mV dec-1 Tafel slope. Additionally, remarkable HER activity having a minimal overpotential of 122 mV along with low Tafel slope up to 89 mV dec-1 was succeeded. Assembled device demonstrated exceptional stability for 40 h, indicating its potential for sustainable water splitting applications. Hence, for sustainable hydrogen production via water splitting, the Fe-doped CoCu2Se4 metals are a promising candidate.
Lowering the operating temperature of proton-conducting ceramic fuel cells (PCFCs) to the technologically critical 400-550 degrees C regime requires a fundamental rethinking of electrolyte design beyond conventional bulkdoping strategies. Here, we introduce surface doping of Ceria with low-content of Co-Al strategy as a distinct materials paradigm, in which ion-transport functionality is preferentially enhanced within a chemically modified near-surface region while preserving the bulk fluorite structure. It is found that the low-level doping of CeO2 with Co, Al, and Co-Al (5%) substantially improves ions transport in electrolyte, as verified through multiscale characterizations, cell performances evaluations, and proton conduction analysis. In Particular, Co-Al (5%) doped-CeO2 ((CeO2|5(Co-Al)s)) simultaneously promotes oxygen-vacancy formation and stabilizes lattice distortion, resulting in comparatively superior cell power densities of 1093 mW cm- 2 at 520 degrees C and 296 mW cm- 2 at 370 degrees C, along with reduced polarization losses and enhanced transport kinetics, as revealed by impedance spectroscopy and distribution relaxation time (DRT) analyses. Further investigation confirms the proton-ions conduction and fuel-cell stability operation of the CeO2|5(Co-Al)s electrolyte-based cell. Moreover, the CeO2|5(Co-Al)s electrolyte achieves a current density of 0.962 A cm- 2 at 1.4 V in electrolysis mode, which preliminary demonstrates the reversibility and potential applicability of the developed electrolyte under electrolysis conditions. These results establish that low-content of surface doping can be employed as a generalizable strategy for electrolyte in low-temperature SOFCs and reversible PCFCs.
