ABSTRACT
Boron-hydrogen (B-H) materials are used as hydrogen and heat sources, due to their reducing potential. It has been shown again with the COVID-19 pandemic that greenhouse gas activities are anthropogenic in origin. In particular, the conversion of carbon dioxide (CO2) into valuable chemicals has an important place in the fight against the climate crisis. The conversion of anthropogenic CO2 into valuable chemicals has important implications for a habitable world. In many studies in the literature, boron hydrides have been used to produce, hydrogen and convert carbon dioxide into valuable chemicals. Formic acid and methanol obtained by hydrogenation can be seen as the clean energy movement of the future with its value in hydrogen storage. The type of valuable chemicals that will be formed by the hydrogenation of CO2 is directly related to the method to be followed. The type of catalyst used, or how much hydrogen molecule interacts with CO2, determines the valuable chemical that will form. Disturbances in the thermodynamics of the hydrogenation of CO2 have been tried to be eliminated by various types of catalysts and necessary condition optimizations. Many catalysts and methods developed for the hydrogenation of CO2 were examined. This study discusses the use of B-H materials via catalytic conversion of CO2 into valuable chemicals in terms of critical factors such as reaction conditions, selection of catalyst, and solvent. © 2022 Proceedings of WHEC 2022 - 23rd World Hydrogen Energy Conference: Bridging Continents by H2. All rights reserved.
ABSTRACT
The gradual depletion of fossil fuel reserves that contribute to ~85% of global energy production and release of toxic effluents urges the transformation toward renewable fuels. Thus, the sustainable utilization of sunlight for water splitting and CO2 reduction with heterogeneous photocatalysts has come to light. As a semiconductor photocatalyst, ZnIn2S4 has hit the limelight owing to its narrow bandgap and visible‐light‐responsive properties. However, the limitations of ZnIn2S4 include limited active sites, fast charge‐carrier recombination, and low photoconversion efficiency. Beginning from the fundamental photocatalytic mechanism, this review then provides in‐depth insights into several modification strategies of ZnIn2S4, extending from defect engineering, facet engineering, cocatalyst loading to junction engineering, enabling the synergistic construction of high‐performance ZnIn2S4‐based systems. Subsequently, the structure‐performance relation of ZnIn2S4‐based photocatalysts for hydrogen evolution (HER), overall water splitting (OWS), and CO2 reduction applications in the last 4 years will be discussed and concluded by the future perspectives of this frontier.
ABSTRACT
Combined heat and power (CHP) generation plants are an assessed valuable solution to significantly reduce primary energy consumption and carbon dioxide emissions. Nevertheless, the primary energy saving (PES) and CO2 reduction potentials of this solution are strictly related to the accurate definition and management of thermal and electric loads. Data-driven analysis could represent a significant contribution for optimizing the CHP plant design and operation and then to fully deploy this potential. In this paper, the use of a bi-level optimization approach for the design of a CHP is applied to a real application (a large Italian hospital in Rome). Based on historical data of the hospital thermal and electric demand, clustering analysis is applied to identify a limited number of load patterns representative of the annual load. These selected patterns are then used as input data in the design procedure. A Mixed Integer Linear Programming coupled with a Genetic Algorithm is implemented to optimize the energy dispatch and size of the CHP plant, respectively, with the aim of maximizing the PES while minimizing total costs and carbon emissions. Finally, the effects of integrating biogas from the Anaerobic Digestion (AD) of the Spent Coffee Ground (SCG) and Energy Storage (ES) technologies are investigated. The results achieved provide a benchmark for the application of these technologies in this specific field, highlighting performances and benefits with respect to traditional approaches. The effective design of the CHP unit allows for achieving CO2 reduction in the order of 10%, ensuring economic savings (up to 40%), when compared with a baseline configuration where no CHP is installed. Further environmental benefits can be achieved by means of the integration of AD and ES pushing the CO2 savings up to 20%, still keeping the economical convenience of the capital investment.