Fe-Beta zeolite for selective catalytic reduction of NO_x with NH_3:Influence of Fe content

Fe doped Beta zeolite with different Fe contents were prepared by ion exchange by changing the volume or the concentration of a Fe salt solution. For a particular mass of Fe salt precursor, the concentration of the metal salt solution during ion exchange influenced the ion exchange capacity of Fe, and resulted in different activities of the Fe-Beta catalyst. Fe-Beta catalysts with the Fe contents of （2.6, 6.3 and 9） wt% were synthesized using different amounts of 0.02 mol/L Fe salt solution. These catalysts were studied by various characterization techniques and their NH3-SCR activities were evaluated. The Fe-Beta catalyst with the Fe content of 6.3 wt% exhibited the highest activity, with a temperature range of 202-616℃ where the NOx conversion was 〉 80%. The Fe content in Beta zeolite did not influence the structure of Beta zeolite and valence state of Fe. Compared with the Fe-Beta catalysts with low Fe content （2.6 wt%）, Fe-Beta catalysts with 6.3 wt% Fe content possessed more isolated Fe3. active sites which led to its higher NH3-SCR activity. A high capacity for NH3 and NO adsorption, and a high activity for NO oxidation also contributed to the high NH3-SCR activity of the Fe-Beta catalyst with 6.3 wt%. However, when the Fe content was further increased to 9.0 wt%, the amount of FexOy nanoparticles increased while the amount of isolated Fe3＋ active sites was unchanged, which promoted NH3 oxidation and decreased the NH3-SCR activity at high temperature.

An odyssey: the way Chinese catalysis towards the world

The 16^th International Catalysis Congress (16th ICC) was successfully held in China in July 2016. This paper reviewed the development of catalytic science and technology of China from scratch to small then to large under the efforts of several generations. In 1950s, catalysis discipline was first set up to train early catalytic professionals in Jilin University, Peking University and Xiamen University. Subsequently, a large research team was formed in colleges and universities, the Academy of Sciences, the Enterprise Research Institute to carry out a large number of catalytic researches. Along with the Chinese reform and opening-up, the spring of science came, and the state started to emphasize and strongly support scientific research. Chinese catalytic researchers began to enter the international catalytic academic exchange platform. Famous foreign scientists are invited to visit China and a large number of visiting scholars and foreign students have been sent to the United States, Europe and Japan, many of them have become well-known professors, and grown into catalytic academic elites. The first China-Japan-USA Symposium on Catalysis was held in Dalian in 1982, and it was expanded to become the Asian-Pacific Congress on Catalysis (APCAT), one of the three regional catalytic conferences in the world. After several generations of bidding for the organization of the International Catalytic Congress three times, China won the right to host the 16th ICC. It has effectively promoted the Chinese catalytic academic circles to the international academic ones and improved the influence of catalysis communities in China significantly. The great development in catalytic research and technology has condensed the efforts of several generations of catalysts. To make China a catalytically strong country, there is still a long way to go. We hope that the contemporary scientists can accomplish this historical task.

Highly active iridium catalyst for hydrogen production from formic acid

Formic acid（FA） dehydrogenation has attracted a lot of attentions since it is a convenient method for H_2 production. In this work, we designed a self-supporting fuel cell system, in which H_2 from FA is supplied into the fuel cell, and the exhaust heat from the fuel cell supported the FA dehydrogenation. In order to realize the system, we synthesized a highly active and selective homogeneous catalyst Ir Cp＊Cl_2 bpym for FA dehydrogenation. The turnover frequency（TOF） of the catalyst for FA dehydrogenation is as high as7150 h^（-1）at 50°C, and is up to 144,000 h^（-1）at 90°C. The catalyst also shows excellent catalytic stability for FA dehydrogenation after several cycles of test. The conversion ratio of FA can achieve 93.2%, and no carbon monoxide is detected in the evolved gas. Therefore, the evolved gas could be applied in the proton exchange membrane fuel cell（PEMFC） directly. This is a potential technology for hydrogen storage and generation. The power density of the PEMFC driven by the evolved gas could approximate to that using pure hydrogen.