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.

A series of ZIF-67-C-IL catalysts were prepared using ZIF-67 and 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide ([ BMIM]NTf2) ionic liquid as precursors. The structure of the catalysts was characterized by XRD, TEM, SEM and XPS. The catalytic performance of the catalysts for the oxygen reduction reaction (ORR) was evaluated in a three-electrode system. The results confirmed that the high-temperature treatment of the precursors resulted in the formation of N, S codoped carbon-encapsulated Co9S8 nanoparticles. To create N, S co-doped carbon coated Co9S8 nanoparticle catalysts, ionic liquids are used as sulfur and nitrogen sources. The catalytic activity of ORR can be improved using N, S co-doped carbon to prevent the aggregation of Co9S8 nanoparticles. Graphitized and N, S co-doped carbon shells are optimal for achieving high activity stability. Optimal 600-ZIF-67-C(1:1.5)-30IL catalytic activity was observed for ORR. The half-wave potential of ORR was 0.88 V vs. RHE in 0.1 mol L− 1 KOH, with a limit current density of 4.70 mA cm− 2. Similar ORR electrocatalytic activity was observed between this catalyst and commercial Pt/C (20 wt%).

Bypass line과 Catalyst를 공간적으로 결합한 Bypass 일체형 탈질설비를 제안하였다. 탈질설비 내부에 설치되는 Bypass의 개폐장치 의 형태에 따른 Catalyst로의 유동 변화를 확인하기 위하여 상용프로그램인 Ansys Fluent를 사용하여 탈질설비를 모델링하고 시뮬레이션을 구성하였다. 탈질설비 내의 Catalyst로 인한 계산시간과 Mesh의 수를 줄이기 위해 Porous media방식으로 Catalyst를 모델링하였다. Catalyst로 의 입구각도와 Bypass 개폐장치의 크기를 변화시키면서 시뮬레이션을 수행하고 시뮬레이션의 결과로 Catalyst로의 유동 평균속도와 균일도의 변화를 확인하였다.

본 연구에서는 기존 상용 SCR 촉매보다 비표면적, 경량성 및 온도 응답성이 우수한 SCR 촉매의 개발을 목적으로 바나듐과 텅스텐의 함량과 바인더의 첨가량을 달리하여 Metal foam 형태의 지지체에 코팅하여 SCR 촉매를 제조한 후, 실험실 규모의 마이크로 상압반응기상에서 공간속도별로 NOx 저감 성능을 측정하였다. 촉매의 특성은 Porosimeter, SEM(scanning electron microscope), EDX(energy dispersive x-ray spectrometer) 및 ICP(inductively coupled plasma), 실체현미경(Stereomicroscope) 기기를 이용하여 분석하였다. 연구 결과 NOx 저감 성능은 공간속도가 증가할수록 감소하였고, 바나듐과 텅스텐의 함량이 3.5 wt.% 일 때 가장 우수한 것으로 확인하였다. 또한, 바인더 첨가량이 많을수록 NOx 저감 성능이 감소하는 것으로 나타났는데, 이는 촉매 표면상의 활성점수가 바인더에 의해 점유되어 감소된 것에 따른 것으로 판단된다. 또한 표면 코팅 상태 분석을 통하여 바인더의 첨가량이 적절히 조절 되어야 함을 알 수 있었다.

폐 RHDM(Residue Hydrodemetallation) 촉매상에 침적된 비활성화 성분인 탄소, 황 을 고온배소 처리하여 제거한 후, 과량 침적되어 있는 바나듐은 초음파 교반기에서 5~15wt% 옥살산 수용액을 이용하여 50℃, 5분 조건하에 바나듐 추출량을 조절함으로써 NOx 저감을 위한SCR(Selective Catalytic Reduction) 촉매로의 적용 가능성을 확인하고자 하였다. 폐촉매와 단계별 처리된 RHDM 촉매를 대상으로 상압반응기상에서 NOx 저감 효율을 측정하였고, 촉매의 성분분석은 ICP, C & S analyzer 및 XRF를 이용하여 분석하였다. 10wt% 옥살산 수용액으로 바나듐을 침출한 촉매가 가장 안정적이었으며 높은 NOx 저감 효율을 보였다. 이를 메탈폼 형태의 지지체에 워시코팅한 촉매는 상용 SCR 촉매와 동등 수준의 NOx 저감 효율을 나타내었다. 따라서 폐 RHDM 촉매의 처리 조건 조정에 관한 후속 연구를 통하여 각 적용처에 적합한 SCR 촉매로의 이용 가능성은 충분할 것으로 사료된다.

The cobalt silicides were investigated for employment as a catalytic layer for a DSSC. Using an E-gun evaporation process, we prepared a sample of 100 nm-thick cobalt on a p-type Si (100) wafer. To form cobalt silicides, the samples were annealed at temperatures of 300 oC, 500 oC, and 700 oC for 30 minutes in a vacuum. Four-point probe, XRD, FE-SEM, and CV analyses were used to determine the sheet resistance, phase, microstructure, and catalytic activity of the cobalt silicides. To confirm the corrosion stability, we also checked the microstructure change of the cobalt silicides after dipping into iodide electrolyte. Through the sheet resistance and XRD results, we determined that Co2Si, CoSi, and CoSi2 were formed successfully by annealing at 300 oC, 500 oC, and 700 oC, respectively. The microstructure analysis results showed that all the cobalt silicides were formed uniformly, and CoSi and CoSi2 layers were very stable even after dipping in the iodide electrolyte. The CV result showed that CoSi and CoSi2 exhibit catalytic activities 67 % and 54 % that of Pt. Our results for Co2Si, CoSi, and CoSi2 revealed that CoSi and CoSi2 could be employed as catalyst for a DSSC.

In the present study, potassium and caesium doped Ag/ catalysts were synthesized by simple wet impregnation method and evaluated for selective catalytic reduction (SCR) of NOx using methane. TEM analysis and diffraction patterns demonstrated the finely dispersed Ag particles. BET surface measurements reveal that the prepared materials have moderate to high surface area and the metal amount found from ICP analysis was well matching with the theoretical loadings. The synthesized K-Ag/ and Cs-Ag/ catalysts exhibited a promotional effect on deNOx activity in the presence of and . The long-term isothermal studies at under oxygen rich condition showed the superior catalytic properties of the both alkali promoted samples. The crucial catalytic properties of materials are attributed to NO adsorption properties detected by the NO TPD.

To achieve energy efficiency improvement is used to lower temperature for emission gas at catalyst inlet, or to reduce/stop using steam to reheat emission gas. Saved energy from this process can be used as power source in order to increase generation efficiency. Dry emission gas treatment, on the other hand, is the technology to increase generation efficiency by using highly efficient desalination materials including highly-responsive slaked lime and sodium type chemicals in order to comply with air pollution standards and reduce used steam volume for reheating emission gas. If dry emission gas is available, reheating is possible only with the temperature of 45℃ in order to expect generation efficiency by reducing steam volume for reheating. Retention energy of emission gas from combustion is calculated by emission gas multiplied by specific heat and temperature. In order to obtain more heat recovery from combustion emission gas, it is necessary to reduce not only exothermic loss from boiler facilities but emission calorie of emission gas coming out of boiler facilities. In order to reduce emission calorie of emission gas, it is efficient to realize temperature lowering for the emission gas temperature from the exit of heat recovery facility and reduce emission gas volume. When applying low temperature catalysts, the energy saving features from 0.03% to 2.52% (average 1.28%). When increasing the excess air ratio to 2.0, generation efficiency decreases by 0.41%. When the inlet temperature of the catalyst bed was changed from 210℃ to 180℃, greenhouse gas reduction results were 47.4, 94.8, 118.5, 142.2 thousand tons-CO2/y, CH4 was calculated to be 550.0, 1100.1, 1375.1, 1650.1 kg-CH4/y, and N2O was 275.0, 550.0, 687.6, 825.1 kg-N2O/y. In the case of high efficiency dry flue gas treatment, reduction of greenhouse gases by the change of temperature 120~160℃ and exhaust gas 5,000 ~ 6,500 ㎥/ton is possible with a minimum of 355,461 ton/y of CO2 and minimum 4,125 tons of CH4/y to a maximum of 6,325 ton/y and N2O to a minimum of 2,045 kg/y to a maximum of 3,135 kg/y.

The aim of this study is to evaluate the environmental impacts of recovery of valuable metals from the desulfurizing spent catalyst. Molybdenum, vanadium and nickel widely used in the area of catalysis. But the demand of these metals is full filled by industries. Every year, more than 18,000 tons spent catalysts are discarded. In most countries, spent catalyst is classified as a harmful waste. Thus, metal recovery from spent catalyst has been processed. The recovery process of molybdenum, vanadium and nickel from spent catalyst was mainly carried out wet process. However, this process are not suitable for economics and environmental aspects. Because environmental costs for removal of sulfur in the spent catalyst is high and huge amount of industrial wastewater occurs. Thus, it is necessary to develop a process which is efficient and does not cause pollution than the wet process. Thus, we have studied life cycle assessment about the dry process for the recovery of valuable metals.

V2O5/TiO2 catalysts promoted with Mn were prepared and tested for selective catalytic reduction of NOx in NH3. The effects of promoter content, degree of catalyst loading were investigated for NOx activity while changing temperatures, mole ratio, space velocity and O2 concentration. Among the various V2O5 catalysts having different metal loadings, V2O5(1 wt.%) catalyst showed the highest activity(98%) under wide temperature range of 200-250℃. When the V2O5 catalyst was further modified with 5 wt.% Mn as a promoter, the highest activity(90-47%) was obtained over the low temperature windows of 100-200℃. From Mn-V2O5/TiO2, it was found that by addition of 5 wt.% Mn on V2O5/TiO2 catalyst, reduction activity of catalyst was improved, which resulted in the increase of catalytic activity and NOx reduction. According to the results, NOx removal decreased for 10%, but the reaction temperature down to 100℃.