催化学报
催化學報
최화학보
CHINESE JOURNAL OF CATALYSIS
2015年
2期
197-203
,共7页
李新燕%张肖肖%徐永贞%柳叶%王新平
李新燕%張肖肖%徐永貞%柳葉%王新平
리신연%장초초%서영정%류협%왕신평
氢气活化%氮氧化物吸附%选择性催化还原%氮气选择性%氢溢流
氫氣活化%氮氧化物吸附%選擇性催化還原%氮氣選擇性%氫溢流
경기활화%담양화물흡부%선택성최화환원%담기선택성%경일류
Hydrogen activation%Nitrogen oxide adsorption%Selective catalytic reduction%Nitrogen selectivity%Hydrogen-spillover
研究了Pt/MgO, Pt/γ-Al2O3, Pt/ZrO2和Pt/HZSM-5催化剂上H2选择催化还原消除NOx(H2-SCR)反应。结果发现, H2-SCR活性和N2生成选择性受催化剂中Pt的金属性以及载体的氮氧化物吸附能力影响很大。 HZSM-5的表面酸性使载体对NOx吸附能力较小,使担载Pt以较高的金属性存在,从而导致Pt/HZSM-5催化剂的高活性和高选择性。相反, Pt/MgO和Pt/γ-Al2O3催化剂较差的活性和选择性可归因于其载体的碱性表面、催化剂中Pt较低的金属性以及载体对氮氧化物较大的吸附能力。结合反应的原位红外光谱结果可以认为,在Pt/载体界面处亚硝酸根/硝酸根物种被还原为N2或N2O,取决于该处参与反应的活性H与这些含氮物种的相对数目。
研究瞭Pt/MgO, Pt/γ-Al2O3, Pt/ZrO2和Pt/HZSM-5催化劑上H2選擇催化還原消除NOx(H2-SCR)反應。結果髮現, H2-SCR活性和N2生成選擇性受催化劑中Pt的金屬性以及載體的氮氧化物吸附能力影響很大。 HZSM-5的錶麵痠性使載體對NOx吸附能力較小,使擔載Pt以較高的金屬性存在,從而導緻Pt/HZSM-5催化劑的高活性和高選擇性。相反, Pt/MgO和Pt/γ-Al2O3催化劑較差的活性和選擇性可歸因于其載體的堿性錶麵、催化劑中Pt較低的金屬性以及載體對氮氧化物較大的吸附能力。結閤反應的原位紅外光譜結果可以認為,在Pt/載體界麵處亞硝痠根/硝痠根物種被還原為N2或N2O,取決于該處參與反應的活性H與這些含氮物種的相對數目。
연구료Pt/MgO, Pt/γ-Al2O3, Pt/ZrO2화Pt/HZSM-5최화제상H2선택최화환원소제NOx(H2-SCR)반응。결과발현, H2-SCR활성화N2생성선택성수최화제중Pt적금속성이급재체적담양화물흡부능력영향흔대。 HZSM-5적표면산성사재체대NOx흡부능력교소,사담재Pt이교고적금속성존재,종이도치Pt/HZSM-5최화제적고활성화고선택성。상반, Pt/MgO화Pt/γ-Al2O3최화제교차적활성화선택성가귀인우기재체적감성표면、최화제중Pt교저적금속성이급재체대담양화물교대적흡부능력。결합반응적원위홍외광보결과가이인위,재Pt/재체계면처아초산근/초산근물충피환원위N2혹N2O,취결우해처삼여반응적활성H여저사함담물충적상대수목。
The selective catalytic reduction of NOx by H2 (H2‐SCR) was studied over Pt/MgO, Pt/γ‐Al2O3, Pt/ZrO2, and Pt/HZSM‐5 catalysts. The H2‐SCR activities and N2 selectivities of the catalysts were strongly influenced by the amounts of Pt metal in the catalysts and the NOx adsorption capacities of the supports. The acidic surface of HZSM‐5 increased the amount of metallic Pt on the support, de‐creasing the NOx adsorption capacity, resulting in much higher H2‐SCR activity and N2 selectivity. The inferior activities of Pt/MgO and Pt/γ‐Al2O3 are ascribed to the low amounts of metallic Pt and large NOx adsorption capacities of the supports as a result of their basic surfaces. Based on these results and in situ Fourier transform infrared spectroscopic studies of the reaction, it is proposed that the reduction products of nitrite/nitrate species at the Pt/support interface are N2 or N2O, de‐pending on the relative amounts of active hydrogen and nitrous species involved in the reduction.