Urban Building Carbon Sinks Under the Carbon Neutrality Goal: Research Hotspots, Measurement Frameworks, and Optimization Strategies

In the context of urban carbon neutrality, buildings are shifting from carbon emission sources to potential urban carbon-sink units. Yet existing studies mostly examine single materials or isolated technologies, and a systematic integration of building carbon sinks is still missing. To address this gap, this study reviews literature from 2007–2025 using statistical analysis, bibliometrics, and network analysis to identify research priorities, technological pathways, and development trends. The results show that: (1) Publications have grown steadily, surging after 2020; research has evolved from material carbonation mechanisms to building-system carbon sinks and then to active carbon-capture technologies, indicating strong multidisciplinary integration. (2) A three-stage framework for quantifying and monitoring building carbon sinks has been formed, but current methods differ by scale and no unified standard exists for urban building carbon-sink assessment. (3) A life-cycle enhancement strategy is summarized, including improving carbonation performance with solid-waste utilization, increasing building exposure area, integrating ecological attached sinks with active capture technologies, and reusing crushed construction waste. This review integrates fragmented findings on the carbon-sequestration efficiency of urban buildings and provides references for future urban emission reduction and climate-neutrality goals.