Biological carbon fixation is crucial to the Earth's carbon cycle and is one of the effective ways to transform CO₂ and manage carbon emissions. Chemoautotrophs, with their unique metabolic strategies and environmental adaptability, play an important role in this process. They are able to convert CO₂ into valuable organic products, solving the problem of limited CO₂ utilization. However, the carbon fixation potential of chemoautotrophs in controlled systems has not been fully explored. This review illustrates the possible challenges of stable culture of chemoautotrophic bacteria in bioreactor. Based on this, a series of physical, chemical and biological methods are proposed to regulate the carbon metabolism of chemoautotrophic bacteria and improve their carbon fixation efficiency. Further, the application prospects of chemoautotrophic carbon fixation in controlled systems are expected, including improving the primary productivity of natural ecosystems, reducing carbon emissions in specific sites, and producing high−value microbial by−products. This review highlights the advantages and challenges of these applications, providing important insights into carbon capture, fixation and conversion by chemoautotrophs.

Methanol as fuel, particularly for the green methanol by its clean burning characteristics and easy availability with liquified energy as well as abundant application scenarios is assist it transform from shipping, transportation and industry and so on to the global energy transition as well as realization for the goal of "Double Carbon". According to the transformation of methanol from chemical to fuel, the review reports that various forms of methanol as fuel are used in industry and power units respectively, particularly introducing the status of usages in internal combustion engines and their technical characteristics in applications for reference in futural development. Taking the advantage of the huge productive capability of our country, and promoting the green methanol application as well as its development, many proposals are provided based on the following issues such as the policy support and technical improvements and so on.

This paper systematically reviews the concept of green methanol fuel, and conducts a comparative analysis of the main manufacturing technology paths, emission reduction potential, as well as the advantages and disadvantages for the major routes, including the biomass path, the electricity−based path and the electricity−biomass coupling path, etc. We summarize the relevant policies on methanol fuel for the water transportation industry at the national and industry levels, clearly stating to promote the pilot application of methanol fuel in coastal and inland river vessels, and to accelerate the construction of methanol refueling stations, storage facilities and other supporting facilities. A review has been conducted of the current green methanol−related standards in China, including guidelines for methanol fuel for ships and group standards focusing on the evaluation of green methanol and the carbon footprint assessment of green methanol products. Related policies and standards are still in the initial stage. At the same time, based on the low−emission analysis platform LEAP, a comprehensive assessment model for carbon emissions prediction of China's water transportation industry is constructed to quantitatively calculate the total energy consumption and carbon emissions of China's water transportation industry in the medium and long term. It is estimated that the total energy consumption will be about 58~85 million tce, and the total emissions will decrease to 30~120 million tons CO₂. Based on the above analysis, suggestions for the future development of marine green methanol fuel industry in China are proposed, including: continuously tracking and deeply participating in the IMO’s negotiations on the net−zero framework and related rules construction; combining the internal and external water industry advantages to conduct in−depth quantitative research on the dual−carbon transformation path of the water industry; and taking the lead through trials and experiments, step by step to systematically promote the development of green methanol in China.

Hydrogen energy, recognized globally as a clean energy source, demonstrates significant potential in supporting climate commitments and energy transition. Driven by the "dual carbon" target, China's hydrogen energy industry has entered a rapid development phase. This paper focuses on emerging hydrogen energy application sectors, such as transportation, electricity, and construction. Relevant policies and cases from several developed countries in recent years are summarized. Current status and achievements of domestic hydrogen energy applications in the three sectors are reviewed and also some key issues. Finally, a development pathway for hydrogen energy which conforms to China's national conditions and some forward−looking recommendations are proposed. The purpose of this paper is to provide support for the steady development of hydrogen energy in China.

The dual pressures of urbanization and climate change are intensifying the urban heat island effect, carbon emissions, and air pollution, posing significant challenges to environmental sustainability and urban livability. As the demand for multiobjective coordinated management of urban ecological environments continues to increase, integrating heat, carbon, and pollution into a unified framework for comprehensive assessment has become a key direction for future urban planning and policy−making. This article systematically compares and analyzes the consistency between global development agendas and the goals of reducing urban heat, carbon, and pollution, highlighting the significant potential and advantages of new−generation information technologies in intelligent optimization and coordinated scheduling, data fusion and analysis, real−time monitoring and feedback, and decision support and simulation. From the new perspective of urban spatial form, it comprehensively reviews the specific content, challenges, and future issues in conducting multi−scale, multi−dimensional "heat−carbon−pollution" multi−objective coordinated reduction planning. It provides innovative solutions for multi−objective coordinated management and sustainable development of "heat−carbon−pollution" in Chinese cities.

With China's "Dual Carbon" goals (carbon peaking by 2030 and carbon neutrality by 2060) entering a critical implementation window, the next five years represent a decisive phase for determining the success of this transition. As one of the core supports of clean energy systems, electrochemical energy technology is witnessing unprecedented development opportunities. Based on the latest policy orientations and technological trends, this study analyzes the current status, target pathways, and strategic actions for electrochemical energy storage and conversion against the "countdown" backdrop of the Dual Carbon initiative. Against the escalating global climate crisis and growing energy security concerns, clean energy has emerged as a central direction for the worldwide energy transition. The development of clean energy not only helps reduce dependence on fossil fuels and cut greenhouse gas emissions but also promotes the diversification of energy mix and enhances energy security. Consequently, the clean energy sector is facing new development opportunities and challenges. This study aims to provide a systematic exploration of the development status, technological innovations, market trends, and application prospects across five key areas: electrocatalysis, solar cells, fuel cells, lithium batteries, and bioenergy, thereby offering insights to support the further deployment and sustainable development of clean energy.