The electrochemical reduction of carbon dioxide (CO2) to value-added products is a remarkable approach for mitigating CO2 emissions caused by the excessive consumption of fossil fuels. However, achieving the electrocatalytic reduction of CO2 still faces some bottlenecks, including the large overpotential, undesirable selectivity, and slow electron transfer kinetics. Various electrocatalysts including metals, metals oxides, alloys, and single-atom catalysts have been widely researched to suppress HER performance, reduce overpotential and enhance the selectivity of CO2RR over the last few decades. Among them, single-atom catalysts (SACs) have attracted a great deal of interest because of their advantages over traditional electrocatalysts such as maximized atomic utilization, tunable coordination environments and unique electronic structures. Herein, we discuss the mechanisms involved in the electroreduction of CO2 to carbon monoxide (CO) and the fundamental concepts related to electrocatalysis. Then, we present an overview of recent advances in the design of high-performance noble and non-noble singleatom catalysts for the CO2 reduction reaction.

본 연구에서는 PEBAX 2533에 합성된 PEI-GO@ZIF-8의 함량을 달리 첨가하여 혼합막을 제조하고 N2와 CO2의 투과 특성을 연구하였다. PEBAX/PEI-GO@ZIF-8 혼합막의 N2 투과도는 PEI-GO@ZIF-8 함량이 증가함에 따라 감소하였고, CO2 투과도는 PEI-GO@ZIF-8 함량에 따라 다른 경향을 보였는데 순수 PEBAX 막에서 PEI-GO@ZIF-8 0.1 wt%까지 CO2 투과도는 증가하다가 그 이후의 함량에서는 감소하였다. PEI-GO@ZIF-8 0.1 wt% 혼합막은 CO2 투과도 221.9 Barrer, CO2/N2 선택도는 60.0으로, 제조된 혼합막들 중 CO2 투과도와 CO2/N2 선택도가 향상되어 가장 높은 투과 특성을 보였고 Robeson upper-bound에 도달하는 결과를 얻었다. 이는 충진물이 PEBAX 내에 고루 분산되면서 CO2와 친화적인 상호작용을 하는 GO의 -COOH, -O-, -OH 작용기와 PEI에 결합된 아민기 그리고 CO2에 대해 gate-opening 현상이 일어나는 ZIF-8의 영 향 때문이다.

Crassulacean acid metabolism (CAM) plants use surplus CO2 generated by cooling and heating at night when ventilation is not needed in a greenhouse. Schlumbergera truncata ‘Pink Dew’ is a multi–flowering cactus that needs more phylloclades for high–quality production. This study examined photosynthetic characteristics by the phylloclade levels of S. truncata in a growth chamber and a greenhouse for use of night CO2 enrichment. The CO2 uptake rate of the S. truncata’s top phylloclade in a growth chamber exhibited a C3 pattern, and the second phylloclade exhibited a C3 –CAM pattern. The CO2 uptake rate of the top phylloclade in a greenhouse showed a negative value both day and night, but those of the second phylloclade exhibited a CAM pattern. The stomatal conductance and water–use efficiency (WUE) of S. truncata at both the top and second phylloclades were higher in a growth chamber than in a greenhouse. The WUE of S. truncata in a growth chamber and a greenhouse was higher at the second phylloclade, which is a CAM pattern compared with those of the top phylloclade. The daily total net CO2 uptake of S. truncata was higher in a growth chamber than in a greenhouse. The daily total net CO2 uptake of S. truncata at the second phylloclade had the highest value of 155 mmol·m–2·d–1 in a growth chamber. The night total CO2 uptake of S. truncata at the second phylloclade was 3–fold higher in a growth chamber than in a greenhouse. S. truncata’s second phylloclade exhibited a CAM pattern that uptake CO2 at night, and the second phylloclade, was more mature than the top phylloclade. A multi–flowering cactus S. truncata ‘Pink Dew’ efficiently uptake night surplus CO2 in the proper environmental condition with matured phylloclade.

The conversion of CO2 into solar fuels by photocatalysis is a promising way to deal with the energy crisis and the greenhouse effect. The introduction of oxygen vacancy into semiconductor has been proved to be an effective strategy for enhancing CO2 photoreduction performance. Herein, TiO2- x nanostructures have been prepared by a simple solvothermal method and engineered by the reaction time. With the prolonging of reaction time, the oxygen vacancy signal gradually increases while the band gap becomes narrow for the as-synthesized TiO2- x nanostructures. The results show that the TiO2- x-6 h, TiO2- x-24 h, and TiO2- x-48 h samples have the main product of CH4 (more) and CO (less) for CO2 photoreduction. Among the three oxygen vacancy photocatalysts, the TiO2- x-24 h sample shows the highest CH4 generation rate of 41.8 μmol g− 1 h− 1. On the basis of photo/electrochemical measurements, the TiO2- x-24 h sample exhibits efficient electron–hole separation and charge transfer capabilities, thus allows much more electrons to participate in the reaction and finally promotes the photocatalytic CO2 reduction reaction. It further confirms that the optimization of oxygen vacancy concentration could facilitate the photoinduced charge separation and accordingly improve photocatalytic CO2 conversion.

The physiological characteristics, growth, and yield of each regional rice variety (‘Odaebyeo’, ‘Saechucheong’, ‘Ilmibyeo’) were investigated depending on the impact of changes in temperature and CO2 concentration. Experiments were conducted with a control group, which reflected atmospheric CO2 concentration and temperature, and treatment groups, in which the CO2 concentration and temperature were increased by 250 ppm and 2.0℃ from those in the control group. The results showed that the increase in CO2 concentration and temperature reduced the growth and yield of the rice ‘Odaebyeo’, but did not substantially change the productivity of the ‘Saechucheong’ and ‘Ilmibyeo’. The increase in CO2 concentration and temperature increased stomatal conductance and rate of transpiration of the ‘Odaebyeo’ variety, thereby decreasing its water use efficiency (WUE). In contrast, the increase in CO2 concentration and temperature increased the photosynthetic rate and WUE of the ‘Saechucheong’ and ‘Ilmibyeo’ varieties. The gradual change in climate is considered to directly affect growth and development of rice and diversely affect the productivity of each variety. Therefore, it is necessary to implement technological development, select regionally optimal rice varieties, develop new rice varieties, as well as conduct long-term monitoring of each rice variety for climate adaptation to counter global warming.

The biocarbon (SKPH) was obtained from Sargassum spp., and it was evaluated electrochemically as support for the CO2 reduction. The biocarbon was synthesized and activated with KOH, obtaining a high surface area (1600 m2 g− 1) due to the activation process. Graphitic carbon formation after pyrolysis was confirmed by Raman spectroscopy. The XRD results show that SKPH has an amorphous structure with peaks corresponding to typical amorphous carbonaceous materials. FTIR was used to determine the chemical structure of SKPH. The bands at 3426, 2981, 2851, and 1604 cm− 1 correspond to O–H, C-H, and C-O stretching vibrations, respectively. Then, it compares SKPH films with different carbon films using two electrolytic systems with and without charge transfer. The SKPH film showed a capacitive behavior in the KOH, H2SO4, and, KCl systems; in the acid medium, the presence of a redox couple associated with carbon functional groups was shown. Likewise, in the [Fe(CN)6]−3 and Cu(II) systems, the charge transfer process coupled with a capacitive behavior was described, and this effect is more noticeable in the [Fe(CN)6]−3 system. Electrodeposition of copper on SKPH film showed two stages Cu(NH 3)2+ 4 /Cu(NH 3)+ 2 and Cu(NH 3)+ 2 ∕Cu in ammonia media. Hydrogen formation and the activity of CO2 are observed on SKPH film and are favored by the carbon’s surface chemistry. Cu/SKPH electrocatalyst has a catalytic effect on electrochemical reduction of CO2 and inhibition of hydrogen formation. This study showed that the SKPH film electrode responds as a capacitive material that can be used as an electrode for energy storage or as metal support.

Enhancing the capacitive deionization performance requires the inner structure expansion of porous activated carbon to facilitate the charge storage and electrolyte penetration. This work aimed to modify the porosity of coconut-shell activated carbon (AC) through CO2 activation at high temperature. The electrochemical performance of CO2- activated AC electrodes was evaluated by cyclic voltammetry, charge/discharge test and electrochemical impedance spectroscopy, which exhibited that AC-800 had the superior performance with the highest capacitance of 112 F/g at the rate of 0.1 A/g and could operate for up to 4000 cycles. Furthermore, in the capacitive deionization, AC-800 showed salt removal of 9.15 mg/g with a high absorption rate of 2.8 mg/g min and Ni(II) removal of 5.32 mg/g with a rate close to 1 mg/g.min. The results promote the potential application of CO2- activated AC for desalination as well as Ni-removal through capacitance deionization (CDI) technology.

본 연구는 난방 개시 온도와 CO2 시비의 효율을 알아보기 위해 수행되었다. 난방 개시 온도 실험은 9℃, 12℃, 15℃로 구분하여 목표 온도보다 낮아지면 전기 온열기구가 작동하게 하였다. CO2 시비 농도 실험은 액화탄산가스를 이용하여 무 처리, 500μmol·mol-1, 800μmol·mol-1으로 7시부터 12시까 지 처리하였다. 생육 특성으로 초장, 경경, 엽수, 엽면적, 생체 중, 건물중을 조사하였고, 200g 넘는 과실만을 대상으로 수량 을 조사하여 경제성 분석을 하였다. 상위엽에 대한 광합성 측 정을 하여 처리에 따른 포화점을 산출하였다. 애호박의 광포화 점은 587μmol·m-2·s-1이였고 CO2 포화점은 702μmol·mol-1 이 였다. CO2에 의한 Amax값은 9℃, 12℃, 15℃, 500μmol·mol-1, 800μmol·mol-1 순으로 13.4, 17.8, 17.2, 19.6, 17.5μmol CO2·m-2·s-1이었다. 온도 실험에서 9℃는 생육과 착과가 정상 적으로 이루어지지 않았다. 12℃와 15℃는 9℃보다 높았지 만 생육과 생산에서 유의미한 차이를 보이지 않았다. CO₂ 농 도 실험은 생육에서 처리구간 유의한 차이를 보이지 않았지만 800μmol·mol-1의 생산성이 가장 좋았다. 이상의 결과를 종합 적으로 보면 난방 개시 온도는 15℃인 것은 작물 생육과 생산 에는 좋았지만 12℃와 유의적인 차이가 없어 경제적 측면에 서 난방 개시 온도를 12℃로 설정하는 것이 좋은 것으로 보이 며, CO2 시비 농도 800μmol·mol-1를 유지하는 것이 생산량 증가에 효과적이었다.

‘탄소중립’에 대한 관심이 높아짐에 따라 CO2를 농업적으 로 이용하기 위한 시도가 증가하고 있다. 본 실험은 발전소에 서 부산물로 배출되는 CO2를 포집하여 액화·정제 후 시설 엽 채류의 생육 및 생산성 증대를 위한 시비용 CO2로의 활용 가 능성을 평가하기 위해 수행되었다. 경상남도 하동지역의 부추, 취나물, 미나리 농장에 드라이아이스가 공급되었고 각 농 장의 온실 중 하나의 온실은 대조군, 하나의 온실은 CO2 처리 구로 사용되었다. CO2의 시비는 자체 제작한 장치를 사용하 여 드라이아이스에서 승화된 가스를 온실에 공급했다. 부추 온실은 대조군과 CO2 처리에서 온실 내 CO2 농도의 차이가 없었고 두 온실 모두 높은 CO2 농도를 보였다. 반면에 취나물 과 미나리 온실에서는 CO2 시비 처리에서 높은 CO2 농도가 측정되었다. 취나물 및 미나리의 생육은 CO2 시비 처리구에 서 유의성 있게 증가하였으며 수확량도 각각 36%와 25%로 증가하였다. 경제성 분석 결과, 취나물 농가에서는 소득률이 증가하였지만, 부추와 미나리 농가는 감소하는 것으로 나타 났다. 따라서 화력발전소에서 부산물로 발생한 드라이아이스 의 이용은 시설 엽채류의 생산성을 높일 수 있었다

Although the effect of elevated carbon dioxide (CO2) on Phalaenopsis plant flowering, biomass, and photosynthesis has received intensive study, whether elevated CO2 affects plant requirements and sensitivity to potassium sulfate (SOP) during the reproductive growth stage remains unclear. To evaluate the combined effect of CO2 and SOP provision on crassulacean acid metabolism orchids, we cultivated Phalaenopsis Queen Beer ‘Mantefon’ under ambient and elevated CO2 treatments (≈ 400 or ≈ 720 μmol×mol-1, respectively) and four levels of SOP supply for 20 weeks after treatments (WAT): potassium and sulfate levels by 10.41 and 1.96 mmol·L-1 (SOP1), 5.98 and 0.90 mmol·L-1 (SOP2), 12.80 and 1.96 mmol·L-1 (SOP3), and 14.83 and 3.16 mmol·L-1 (SOP4), respectively. The number of floral buds and flowers decreased in the plants grown under elevated CO2 than in those grown under ambient CO2, regardless of the SOP level; however, the reduced production of floral buds and flowers did not affect the dry mass of shoot, root, and spike at 20 WAT. There were significant interactive effects of CO2 and SOP on root biomass accumulation and net CO2 uptake. The stimulation of biomass partitioning on the root, as a sink source, observed due to the uptake of elevated CO2 was improved under increased SOP supply. Under ambient CO2, the leaf critical SOP level was SOP1 for root and spike biomass accumulation. Plants grown under elevated CO2 were more sensitive to SOP treatments, with higher essential leaf levels of SOP.

The slaughter of livestock is inevitably required to obtain meat products from livestock. Since slaughter means pain and death for animals, reducing the pain and distress of animals during slaughter is very important from a perspective of animal welfare based on the principle of respect for life. Generally, two stunning methods, CO2 stunning and electrical stunning, are used for slaughter. When the carotid arteries of the lungs are cut off for bleeding, the bronchial tubes are also severed. To determine the degree of blood inflow into the lungs through the severed bronchial tubes, the prevalence rates of pulmonary diseases and pulmonary congestion in slaughtered pigs were analyzed. In this study, the prevalence of pneumonia was 24.9% in Slaughterhouse A using the gas method, but it was decreased by about 10% to 15.7% and 12.6%, respectively, in Slaughterhouses B and C using the electric method. On the other hand, the prevalence of pulmonary congestion in Slaughterhouses A, B, and C was 4.24%, 14.10% and 16.40%, respectively. In other words, the prevalence of pulmonary congestion was higher by about 10% in the groups of pigs slaughtered by the electric method (Slaughterhouses B and C) than in the group of pigs slaughtered by the gas method (Slaughterhouse A). These results indicate that blood inflow into the pulmonary alveoli led to a diagnosis of pulmonary congestion instead of pneumonia in some pigs with pneumonia. In short, it was found that about 10% of pigs stunned by the electric method were not in a state of complete unconsciousness but in a partially conscious state during slaughter. It is suggested that slaughterhouses should be equipped with gas stunning equipment instead of applying the electric method due to lower costs.

대용량 화학 및 청정에너지의 운반체인 수소는 석유화학 산업 및 연료전지 등에서 많이 활용되는 중요한 산업용 기체이다. 특히 수소는 주로 증기개질 및 가스화를 통해 화석 연료에서 생성되며 부산물로 이산화탄소가 발생한다. 따라서 고 순도 수소를 얻기 위해서는 이산화탄소를 제거해야 한다. 본 총설에서는 배러 단위[1 Barrer = 10−10 cm3 (STP) × cm / (cm2 × s × cmHg)]로 보고된 이산화탄소로부터 수소를 분리하는 프리스탠딩 고분자 분리막 및 혼합매질 분리막에 초점을 맞추었 다. 최근 보고된 다양한 논문들을 분석하여 분리막의 구조, 형태, 상호 작용 및 제조 방법에 대해 논의하고 구조-물성 관계를 이해하여 향후 더 나은 분리막 소재를 찾는 데 도움이 되고자 한다. 다양한 분리막의 성능 및 특성 검토를 통해 수소/이산화 탄소 분리에 대한 Robeson 성능 한계선을 제시하고, 가교, 혼합 및 열처리 등의 기술을 사용하여 분리 특성을 개선하는 다양 한 혼합매질 분리막에 대해 논의하였다.