탄소중립을 달성하기 위해 이산화탄소를 포집, 활용, 저장하는 CCUS (carbon capture, utilization, and storage) 기 술이 주목받고 있다. 본 연구에서는 광물 탄산화 공정을 통해 이산화탄소를 탄산염으로 고정하고, 이를 전이금속 탄산염 기반 리튬이온배터리 (LIB) 음극재로 적용하였다. CO2를 탄산염으로 고정후, 이를 이용해 FeCO3를 제작하고, rGO와 PVP와 복합 화하여 음극활물질에 적용하였다. rGO는 전기전도도를 높이고 입자의 응집을 방지해 부피 팽창을 완화했으며, PVP는 계면 활성제로서 입자 표면을 안정화하여 구조적 안정성을 강화하였다. FeCO3-PVP-rGO 복합체 기반한 음극재에 대한 전기화학 테스트를 진행한 결과, FeCO3/rGO 복합체는 1,620 mA/g의 전류 밀도에서 50 사이클 이후에도 400 mAh/g의 용량을 유지하 였다. 본 연구는 CO2를 고부가가치 배터리 소재로 전환하여 차세대 에너지 저장 기술에 기여할 가능성을 시사한다.

Among the products of the electrocatalytic reduction of carbon dioxide (CO2RR), CO is currently the most valuable product for industrial applications. However, poor stability is a significant obstacle to CO2RR. Therefore, we synthesized a series of bimetallic organic framework materials containing different ratios of tungsten to copper using a hydrothermal method and used them as precursors. The precursors were then subjected to pyrolysis at 800 °C under argon gas, and the M-N bimetallic sites were formed after 2 h. Loose porous structures favorable for electrocatalytic reactions were finally obtained. The material could operate at lower reduction potentials than existing catalysts and obtained higher Faraday efficiencies than comparable catalysts. Of these, the current density of WCu-C/N (W:Cu = 3:1) could be stabilized at 7.9 mA ‧ cm-2 and the FE of CO reached 94 % at a hydrogen electrode potential of -0.6 V (V vs. RHE). The novel materials made with a two-step process helped to improve the stability and selectivity of the electrocatalytic reduction of CO2 to CO, which will help to promote the commercial application of this technology.

Schlumbergera truncata absorbs CO2 through its mature phylloclades during the night, and can use a substantial amount of CO2 without requiring ventilation. This study investigated the growth and photosynthetic responses of S. truncata ‘Red Candle’ at two CO2 levels—ambient (≈ 400 μmol･mol-1) and elevated (≈ 1000 μmol･mol-1). At 0–8 weeks after treatment (WAT), width and length of mature phylloclade and length of immature phylloclade did not differ significantly among the CO2 treatments. At 4–8 WAT, number of branches and phylloclades were significantly greater in plants grown under ambient CO2 than those under elevated CO2. Net CO2 uptake was highest in mature phylloclades of plants grown under ambient and elevated CO2 regimes at night, at 2.51 and 1.30 μmol·CO2·m-2·s-1, respectively. However, no statistically significant variation was observed at 6 WAT, and stomatal conductance was significantly affected only by CO2 uptake time at 6 and 8 WAT. Water-use efficiency of mature and immature phylloclades at night increased with increase in CO2 levels (r = 0.7462 and 0.9312, respectively). At 123 days after treatment, plants grown under elevated CO2 had 82.7 floral buds, compared to 72.1 buds in those under ambient CO2. However, this difference was not statistically significant. Moreover, S. truncata grown under elevated CO2 exhibited decreased growth and photosynthesis, whereas the number of floral buds did not exhibit any significant differences among the treatments.

Artificial photosynthesis harnesses clean and sustainable solar power to catalyze the conversion of CO2 and H2O molecules into valuable chemicals and O2. This sustainable approach combines energy conversion with environmental pollution control. Non-oxide photocatalysts with broad visible-light absorption and suitable band structures, hold immense potential for CO2 conversion. Nevertheless, they still face numerous challenges in practical applications, particularly in CO2 conversion with H2O. Surface modification and functionalization play the significant role in improving the activity of non-oxide photocatalysts. Multifarious strategies, such as cocatalyst loading, surface regulation, doping engineering, and heterostructure construction, have been explored to optimize light harvesting, bandgap driving force, electron–hole pairs separation/transfer, CO2 adsorption, activation, and catalysis processes. This review summarizes recent progress in surface modification strategies for non-oxide photocatalysts and discusses their enhancement mechanisms for efficient CO2 conversion. These insights are expected to guide the design of high-performance non-oxide photocatalyst systems.

CO2 photocatalytic reduction is a carbon–neutral renewable energy technology. However, this technology is restricted by the low utilization of photocatalytic electrons. Therefore, to improve the separation efficiency of photogenerated carriers and enhance the performance of CO2 photocatalytic reduction. In this paper, g-C3N4/Pd composite with Schottky junction was synthesized by using g-C3N4, a two-dimensional material with unique interfacial effect, as the substrate material in combination with the co-catalyst Pd. The composite of Pd and g-C3N4 was tested to have a strong localized surface plasmon resonance effect (LSPR), which decreased the reaction barriers and improved the electron utilization. The combination of reduced graphene oxide (rGO) created a π–π conjugation effect at the g-C3N4 interface, which shortened the electron migration path and further improved the thermal electron transfer and utilization efficiency. The results show that the g-C3N4/ rGO/Pd (CRP) exhibits the best performance for photocatalytic reduction of CO2, with the yields of 13.57 μmol g− 1 and 2.73 μmol g− 1 for CO and CH4, respectively. Using the in situ infrared test to elucidate the intermediates and the mechanism of g-C3N4/rGO/Pd (CRP) photocatalytic CO2 reduction. This paper provides a new insight into the interface design of photocatalytic materials and the application of co-catalysts.

This paper reports an enhanced strategy for improving the mechanical flexibility and ionic kinetic properties of a double network hydrogel based on Co2+- coordination assistance. The modified double-network hydrogel was obtained by using acrylic acid and N, N-dimethylacrylamide as monomers, adding cross-linking agents and 3D nitrogen-doped graphenes. The tensile fracture rate of the modified hydrogel was 1925% and its tensile strength was 1696 kPa. In addition, the hydrogel exhibited excellent ionic dynamics, and its application to an all-solid-state supercapacitor was able to achieve a specific capacitance of up to 182.8 F g− 1. The supercapacitor exhibited an energy density of 34.2 Wh kg− 1, even when operating at a power density of 5 kW kg− 1, highlighting its significant potential for practical applications.

The objective of this study is to analyze the indoor air quality of multi-use facilities using an IoT-based monitoring and control system. Thise study aims to identify effective management strategies and propose policy improvements. This research focused on 50 multi-use facilities, including daycare centers, medical centers, and libraries. Data on PM10, PM2.5, CO2, temperature, and humidity were collected 24 hours a day from June 2019 to April 2020. The analysis included variations in indoor air quality by season, hour, and day of the week (including both weekdays and weekends). Additionally, ways to utilize IoT monitoring systems using big data were propsed. The reliability analysis of the IoT monitoring network showed an accuracy of 81.0% for PM10 and 76.1% for PM2.5. Indoor air quality varied significantly by season, with higher particulate matter levels in winter and spring, and slightly higher levels on weekends compared to weekdays. There was a positive correlation found between outdoor and indoor pollutant levels. Indoor air quality management in multi-use facilities requires season-specific strategies, particularly during the winter and spring. Furhtermore, enhanced management is necessary during weekends due to higher pollutant levels.