A series of bifunctional catalysts are prepared by loading Pd, Ni₂P and bimetallic Pd–Ni₂P on di-n-butylamine(DBA)-templated SAPO-31 molecular sieves through either impregnation or impregnation combined with temperature-programmed reduction methods. All bifunctional catalysts are characterized using XRD, N₂ adsorption, ²⁷Al and ³¹P MAS NMR, SEM, TEM, IR spectroscopy of adsorbed pyridine, XPS, H₂ chemisorption, ICP, and TG–DTG measurements. The catalytic performance over all prepared bifunctional catalysts is compared for n-hexadecane hydroisomerization. The obtained results demonstrate that the 0.05Pd–4Ni₂P/S31 catalyst produces a higher iso-C₁₆ yield of 72.7% with n-C₁₆ conversion of 83.1% compared with the other two catalysts. This result is attributed to two reasons: i) the bimetallic Pd–Ni₂P component possesses stronger (de)hydrogenation functionality than Ni₂P does, and ii) the bimetallic bifunctional catalyst has a better balance between metal and acid functionality than the monometallic catalysts do. Moreover, the 0.05Pd–4Ni₂P/S31 catalyst also shows the best catalytic stability among all catalysts, since the n-C₁₆ conversion and iso-C₁₆ selectivity are still above 80% and 90%, respectively, even after 100 h of long-term testing. Therefore, the present study has provided a novel idea for the design of bimetallic bifunctional catalysts for long-chain n-alkane hydroisomerization.

中文翻译：

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在Pd–Ni ₂ P / SAPO-31双功能催化剂 上正十六烷的加氢异构化：双金属活性位点的协同作用†

通过浸渍或浸渍结合程序升温还原方法，在二正丁胺（DBA）模板的SAPO-31分子筛上负载Pd，Ni ₂ P和双金属Pd-Ni ₂ P ，制备了一系列双功能催化剂。使用XRD，N ₂吸附，²⁷ Al和³¹ P MAS NMR，SEM，TEM，吸附的吡啶的IR光谱，XPS，H ₂化学吸附，ICP和TG-DTG进行表征。比较了所有制备的双功能催化剂的催化性能，以进行正十六烷加氢异构化。获得的结果表明，0.05Pd–4Ni ₂与其他两种催化剂相比，P / S31催化剂产生的异C ₁₆产率更高，为72.7％，n -C ₁₆转化率为83.1％。该结果归因于两个原因：i）双金属Pd–Ni ₂ P组分比Ni ₂ P具有更强的（脱）加氢官能度； ii）双金属双官能催化剂比单金属具有更好的金属和酸官能平衡催化剂呢。此外，由于n -C ₁₆转化率和iso-C ₁₆转化率，0.05Pd–4Ni ₂ P / S31催化剂在所有催化剂中也表现出最佳的催化稳定性。即使经过100小时的长期测试，选择性仍分别高于80％和90％。因此，本研究为长链正构烷烃加氢异构化双金属双功能催化剂的设计提供了新思路。