SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4347-9
Overcoming the intrinsic loading ceiling of oxide-supported single-atom catalysts remains a long-standing challenge, because oxide frameworks generally provide limited capacity for accommodating high densities of isolated metal species. Here, we report a hollow TiO2 nanoreactor that effectively addresses the long-standing loading limitation of oxide-supported catalysts by coupling high-capacity ion exchange with structural confinement. The multiscale framework is derived from a sodium titanate hollow flower-sphere assembled from ultrathin nanosheets. It enables broad accessibility of exchange sites and facilitates high Cu uptake prior to oxide formation. Subsequently, during Ar-assisted transformation into oxygen-vacancy-rich TiO2, the incorporated Cu species remain highly dispersed within the framework, while vacancy-mediated metal–support interactions further enhance their stability. As a result, controllable Cu speciation is achieved at ultrahigh loadings of 7.4 wt% as spatially isolated single atoms and 12.4 wt% as single-atom/subnanometer-cluster hybrids. The optimized hybrid catalyst delivers a hydrogen evolution rate of 28.8 mmol g−1 h−1 under simulated sunlight, surpassing conventional low-loading Cu/TiO2 systems under comparable conditions. This strategy is readily extendable to other transition metals (Fe, Co, and Ni), establishing a structural design principle for constructing high-density and speciation-controlled metal sites on oxide supports.
The Chinese Journal of Process Engineering•2026•DOI: 10.12034/j.issn.1009-606X.225184
Thermal power units have long dominated China's energy structure due to the low cost of coal and their role in ensuring grid stability. However, under the dual pressures of climate change and national carbon peaking/neutrality goals, the environmental impact of their 'three wastes' has become critical, necessitating energy-saving retrofits. This review systematically examines mainstream energy-saving technologies for thermal power units, including boiler combustion optimization, heating surface cleaning, turbine flow path upgrades, waste heat recovery and cascade utilization, and cold-end system optimization. Using coal consumption rate as the core economic index, the study integrates case studies and operational data from typical domestic and international units to evaluate the latest progress, practical effects, advantages, and limitations of each technology. Results indicate that these technologies significantly improve energy efficiency and reduce pollution. For instance, boiler combustion optimization based on support vector machines and neural networks enhances thermal efficiency and reduces NOx emissions. Turbine flow path modifications, from full three-dimensional CFD optimization to advanced blades and combined steam seals, yield notable gains in cylinder efficiency and heat rate reduction. Low-temperature economizers reduce coal consumption and auxiliary power/water use in dust removal and desulfurization systems. Heat pump applications include absorption, compression, and hybrid types. In cold-end optimization, data-driven predictive maintenance and real-time performance tuning of condensers achieve nearly 50% energy savings in circulating water pumps and an average coal consumption reduction of 2-3 g/(kW·h). Despite these advances, gaps remain in multi-objective optimization robustness, intelligent diagnosis, and advanced materials. Future research should focus on deep reinforcement learning for adaptive control, sensor networks for real-time diagnostics and predictive maintenance, and high-temperature corrosion-resistant materials for heat exchangers, while balancing initial investment and maintenance costs.