Frontiers in Energy最新文献

With the development of renewable energy technologies, the recovery and utilization of low-grade energy based on hydroelectric effect have drawn much attention owing to its environmental friendliness. Herein, a novel hydroelectric generator utilizing sodium alginate-graphene oxide (SA-GO) fibers is proposed, which is ecofriendly and low-cost. These fibers with a length of 5 cm and a diameter of 0.15 mm can generate an open circuit voltage (V_oc) of approximately 0.25 V and a short circuit current (I_sc) of 4 µA. By connecting SA-GO fibers in either series or parallel, this combination can power some electronic devices. Furthermore, these fibers enable the recovery of low-grade energy from the atmosphere or around the human body. Both experimental and theoretical analysis confirm that the directional flow of protons driven by water molecules is the main mechanism for power generation of SA-GO fibers. This study not only presents a simple energy transformation method that is expected to be applied to our daily life, but also provides a novel idea for the design of humidity electricity-generation devices.

Using the electrochemical technology to split water molecules to produce hydrogen is the key to obtain green hydrogen for solving the energy crisis. The large-scale application of hydrogen evolution reaction (HER) in water dissociation requires a highly active catalyst. In this paper, the highly dispersed PtCo bimetallic nanoparticles loading on MXene (PtCo/MXene) were prepared by using a step-to-step reduction strategy. The mentioned PtCo/MXene catalyst exhibits a high current density of −100 mA/cm² in an acidic medium with just a 152 mV overpotential. In addition, the PtCo/MXene catalyst also displays a superior stability. Computational analysis and experimental testing demonstrate that the electronic interaction between Pt and Co can effectively modify the electronic structure of the active site, thereby enhancing the inherent catalytic performance of the material. More importantly, MXene two-dimensional nanosheets can expose more active sites because of their large specific surface area. Furthermore, MXene substrate with excellent electrical conductivity and harmonious interfaces between PtCo and MXene enhance charge transfer efficiency and lower the reaction activation energy.

The development of renewable and affordable energy is crucial for building a sustainable society. In this context, establishing a sustainable infrastructure for renewable energy requires the integration of energy storage, specifically use of renewable hydrogen. The hydrogen evolution reaction (HER) of electrochemical water splitting is a promising method for producing green hydrogen. Recently, two-dimensional nanomaterials have shown great promise in promoting the HER in terms of both fundamental research and practical applications due to their high specific surface areas and tunable electronic properties. Among them, molybdenum disulfide (MoS₂), a non-noble metal catalyst, has emerged as a promising alternative to replace expensive platinum-based catalysts for the HER because MoS₂ has a high inherent activity, low cost, and abundant reserves. At present, greatly improved activity and stability are urgently needed for MoS₂ to enable wide deployment of water electrolysis devices. In this regard, efficient strategies for precisely modifying MoS₂ are of interest. Herein, the progress made with MoS₂ as an HER catalyst is reviewed, with a focus on modification strategies, including phase engineering, morphology design, defect engineering, heteroatom doping, and heterostructure construction. It is believed that these strategies will be helpful in designing and developing high-performance and low-cost MoS₂-based catalysts by lowering the charge transfer barrier, increasing the active site density, and optimizing the surface hydrophilicity. In addition, the challenges of MoS₂ electrocatalysts and perspectives for future research and development of these catalysts are discussed.

In this study, the Lewis doping approach of polyaniline (PANI) was employed to fabricate cobait–nitrogen–carbon (Co-N-C) oxygen electrocatalysts for Zn–air batteries, aiming to enhance the active spots of Co-N-C. This resulting Co-N-C catalysts exhibited well-defined nanofiber networks, and the Brunauer-Emmett-Teller (BET) analysis confirmed their substantial specific surface area. Electrochemical experiments demonstrated that the Co-N-C catalysts achieved the half-wave potential (vs. RHE) of 0.85 V in alkaline medium, overcoming Pt/C and iron–nitrogen–carbon (Fe-N-C) counterparts in extended cycle testing with only a 25 mV change in a half-wave potential after 5000 cycles. Remarkably, the highest power density measured in the zinc (Zn)–air battery reached 227 mW/cm², a significant improvement over the performance of 101 mW/cm² of the platinum on activated carbon (Pt/C) catalyst. These findings highlight the advantageous stability enhancement associated with the utilization of Co in the Co-N-C catalysts.

Solar-driven hydrogen production from seawater attracts great interest for its emerging role in decarbonizing global energy consumption. Given the complexity of natural seawater content, photocatalytic vapor splitting offers a low-cost and safe solution, but with a very low solar-to-hydrogen conversion efficiency. With a focus on cutting-edge photothermal–photocatalytic device design and system integration, the recent research advances on vapor splitting from seawater, as well as industrial implementations in the past decades were reviewed. In addition, the design strategies of the key processes were reviewed, including vapor temperature and pressure control during solar thermal vapor generation from seawater, capillary-fed vaporization with salt repellent, and direct photocatalytic vapor splitting for hydrogen production. Moreover, the existing laboratory-scale and industrial-scale systems, and the integration principles and remaining challenges in the future seawater-to-hydrogen technology were discussed.

This paper proposes a new power generating system that combines wind power (WP), photovoltaic (PV), trough concentrating solar power (CSP) with a supercritical carbon dioxide (S-CO₂) Brayton power cycle, a thermal energy storage (TES), and an electric heater (EH) subsystem. The wind power/photovoltaic/concentrating solar power (WP–PV–CSP) with the S-CO₂ Brayton cycle system is powered by renewable energy. Then, it constructs a bi-level capacity-operation collaborative optimization model and proposes a non-dominated sorting genetic algorithm-II (NSGA-II) nested linear programming (LP) algorithm to solve this optimization problem, aiming to obtain a set of optimal capacity configurations that balance carbon emissions, economics, and operation scheduling. Afterwards, using Zhangbei area, a place in China which has significant wind and solar energy resources as a practical application case, it utilizes a bi-level optimization model to improve the capacity and annual load scheduling of the system. Finally, it establishes three reference systems to compare the annual operating characteristics of the WP–PV–CSP (S-CO2) system, highlighting the benefits of adopting the S-CO₂ Brayton cycle and equipping the system with EH. After capacity-operation collaborative optimization, the levelized cost of energy (LCOE) and carbon emissions of the WP–PV–CSP (S-CO₂) system are decreased by 3.43% and 92.13%, respectively, compared to the reference system without optimization.

As a clean and efficient renewable energy source, solar energy has been rapidly applied worldwide. The growth rate of China’s installed capacity ranks first in the world. However, the life span of photovoltaic (PV) modules is 25 to 30 years, and the rapid development of installed capacity indicates that a large number of PV modules will be decommissioned in the future. Therefore, the ongoing treatment of the scrapped PV waste cells in the near future requires urgent plans and countermeasures. Proper recycling and disposal of decommissioned PV modules is a practical requirement for the sustainable development of the country and industry. Crystalline silicon (c-Si) solar cells currently occupy 85%–90% of the market share, and some scholars have begun to seek the utilization pathways of the waste Si in and outside the PV industry. In this paper, the research status of the separation and recycling process of crystalline Si PV modules is reviewed, and the recycling ways of crystalline silicon are particularly focused on. In addition, the current bottlenecks in the PV recycling industry in China are analyzed and some suggestions on the sustainable development of the PV industry are proposed.