Jun Zhu,Jun Chen,Jianan Chen,Jicheng Zhou,Wentao Xu
Direct decomposition of H 2 S into H 2 and S is an attractive alternative to the Claus process, because CO x -free H 2 and S can be simultaneously recovered from an abundant and toxic waste gas, which has huge social economic and ecological environmental benefits. However, it is still a great challenge to achieve the direct H 2 S decomposition reaction with high efficiency due to the thermal equilibrium limitation. Herein, a core-shell structured Mo x C@ZrO 2 was developed as novel microwave catalyst for microwave catalytic H 2 S decomposition. More specifically, the H 2 S conversion over Mo x C@ZrO 2 catalyst is as high as 99.9% at 650 °C, which immensely surpasses the H 2 S equilibrium conversion (6.1% at 650 °C). This study provides an effective strategy for the design of highly active microwave catalysts, and supplies a strategy for efficiently catalytic decomposition of H 2 S waste and recovering high-value hydrogen and sulfur at lower reaction temperatures.
Highly efficient H 2 and S production from copious waste H 2 S is beneficial from both environmental and energy. Whereas, the highly effective direct decomposition of H 2 S reaction faces a gigantic obstacle, that is, there is the severe thermal equilibrium limitation. Herein, a family of TiO 2 modified Mo x C as novel microwave catalysts have been developed. This work demonstrates that Mo 2 C, Mo 2 C-TiO 2 and MoC@TiO 2 microwave catalysts display excellent catalytic performance to recover both valuable H 2 and elemental S from the direct decomposition of H 2 S under microwave irradiation . The optimal H 2 S conversion of MoC@TiO 2 can be as high as 99.9% (almost complete conversion) at 700 °C, which greatly outpaces the corresponding H 2 S equilibrium conversion under microwave irradiation . This result of the chemical equilibrium limitation being broken shows an interesting phenomenon, namely a significant microwave selective catalytic effect by microwave catalysis in H 2 S decomposition reaction . In addition, the apparent activation energy of the Mo 2 C, Mo 2 C-TiO 2 and MoC@TiO 2 microwave catalysts reduced to 18.2 kJ/mol, 16.8 kJ/mol and 15.6 kJ/mol under microwave irradiation. The work supplies a strategy for highly effective valuable H 2 and S production from H 2 S decomposition reaction , and paves a path to high-value utilization of hazardous waste H 2 S resources with energy-saving heating method.
Zhen Wang,Xinbo Ci,Hongjun Dai,Lu Yin,Huixiang Shi
A highly photoactive Ti-containing Cr-modified MCM-48 photocatalyst (Si/Ti = 3.4, Si/Cr = 50) was prepared by a facile one-step method at room temperature. A combination of various physicochemical techniques such as X-ray diffraction (XRD), N 2 physisorption, diffuse reflectance UV–vis spectra (DRS) and X-ray photoelectron spectra (XPS) were used to characterize the properties of the synthetic catalysts. The characterization and experimental results indicated that tetrahedral Ti oxide moieties as dominant Ti oxide were loaded into the mesoporous structure and there was a synergistic interaction between the Ti species anchored on the walls and the Cr ions presented in the MCM-48 framework, which was considered to be directly correlated to the photoactivity. The Ti-Cr-MCM-48 sample can remove H 2 S with the efficiency of 92% under visible light, being the Cr 6+ species primarily responsible for this photoactivity. A deactivation was observed as a consequence of sulfate accumulation on the surface of the catalyst and reduction of Cr 6+ .
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