通过分析钛酞菁（TiPc）、铁酞菁（FePc）、钴酞菁（CoPc）、铜酞菁（CuPc）和镍酞菁（NiPc）5种过渡金属酞菁配合物（TMPcs）的O2吸附能、OH吸附能、H2O2吸附能和H2O吸附能，发现TMPcs的氧还原能力与O2吸附能有一定关系，O2吸附能越大，其氧还原反应催化能力越强.基于密度泛函理论（DFT）和量子力学原理，计算了TiPc的相关吸附能，结果显示：在5种TMPcs中TiPc的O2吸附能力最强；TiPc的O2吸附能大于其OH吸附能；TiPc的O2吸附能远大于其H2O吸附能.在分析TMPcs反应机理的基础上，根据氧还原反应中吉布斯自由能的变化，比较TiPc、FePc、CoPc和Pt作为催化剂的4种情况，理论计算结果表明，TiPc作为催化剂的氧还原反应过程中没有明显的能垒，且速率控制步骤的能垒为零.由此可得，TiPc的氧还原催化能力优于已有实验结果的其他TMPcs和Pt，有可能替代Pt作为质子交换膜燃料电池(PEMFC)的氧化还原催化剂.
The research on non-platinum (Non-Pt) materials as proton exchange membrane fuel cell (PEMFC) catalyst is one of the most important activities in the corresponding fields. Transition metal phthalocyanines (TMPcs) are thought to be potential to replace Pt. Thus, the energies of absorbing O2, OH, H2O2 and H2O on FePc, CoPc, CuPc, NiPc and TiPc surfaces are investigated. It is found that the overall performance of TMPcs as catalyst is related to oxygen adsorption energy, and the higher the value is, the better the overall performance as catalyst. Based on density functional theory (DFT), the TiPc’s adsorption energies are calculated with the following results. First, the oxygen adsorption capacity of TiPc is stronger than that of the other TMPcs. Second, the O2 adsorption energy of TiPc is higher than its OH adsorption energy. Finally, the O2 adsorption energy of TiPc is also much higher than its H2O adsorption energy. Based on the analysis of TMPcs reaction mechanism, the change of Gibbs free energy of TiPc in oxygen reduction reaction is compared with that of FePc, CoPc and Pt. The theoretical calculation shows that TiPc has no obvious energy barrier during the reaction. Based on the above results, it is estimated that the oxygen reduction capacity of TiPc can be better than that of the other TMPcs and Pt, and can be used as a catalyst for PEMFC.
［1］HEBI S, BAYO-BANGOURA M, BAYO K, et al. Electrocatalytic activity of carbon-supported metallophthalocyanine catalysts toward oxygen reduction reaction in alkaline solution［J］. Journal of Solid State Electrochemistry, 2016, 20(4): 931-942.
［2］JACOB T, GODDARD W A. Water formation on Pt and Pt-based alloys: A theoretical description of a catalytic reaction［J］. Chemphyschem, 2005, 7(5): 992-1005.
［3］LIU Y, WU Y Y, LV G J, et al. Iron(II) phthalocyanine covalently functionalized graphene as a highly efficient non-precious-metal catalyst for the oxygen reduction reaction in alkaline media［J］. Electrochimica Acta, 2013,112(12): 269-278.
［4］BRAUN A, TCHERNIAC J. ber die produkte der einwirkung von acetanhydrid auf phthalamid［J］. European Journal of Inorganic Chemistry, 1907, 40 (2): 2709-2714.
［5］DE DIESBACH H, VON DER WEID E. Quelques sels complexes des o-dinitriles avec le cuivre et la pyridine［J］. Helvetica Chimica Acta, 1927, 10 (1): 886-888.
［6］KOBAYASHI N. Phthalocyanines ［J］. Current Opinion in Solid State & Materials Science, 1999, 4(4): 345-353.
［7］JIANG D L, AIDA T. Photoisomerization in dendrimers by harvesting of low-energy photons［J］. Nature, 1997, 388(6641): 454-456.
［8］GE X, SUMBOJA A, WUU D, et al. Oxygen reduction in alkaline media: From mechanisms to recent advances of catalysts［J］. Acs Catalysis, 2015, 5(8): 4643-4667.
［9］DU Chunmiao, LIN Haiping, LIN Bin, et al. MoS2 supported single platinum atoms and their superior catalystic activity for CO oxidation: A density functional theory study［J］. Joumal of Materials Chemistry A, 2015, 3(46): 23113-23119.
［10］YANG S, KIM J, TAK Y J, et al. Single-atom catalyst of platinum supported on titanium nitride for selective electrochemical reactions［J］. Angewandte Chemie, 2016, 55(6): 2058-2062.
［11］JACOB T, MULLER R P, GODDARD W A. Chemisorption of atomic oxygen on Pt(111) from DFT studies of Pt-clusters［J］. Journal of Physical Chemistry B, 2003, 107(35): 9465-9476.
［12］SACHS C, HILDEBRAND M, VOLKENING S, et al. Reaction fronts in the oxidation of hydrogen on Pt (111): Scanning tunneling microscopy experiments and reaction-diffusion modeling［J］. Journal of Chemical Physics, 2002, 116(13): 5759-5773.
［13］VLKENING S, BEDRFTIG K, JACOBI K, et al. Dual-path mechanism for catalytic oxidation of hydrogen on platinum surfaces［J］. Physical Review Letters, 1999, 83（13）: 2672-2675.
［14］CHEN R, LI H, CHU D, et al. Unraveling oxygen reduction reaction mechanisms on carbon-supported Fe-phthalocyanine and Co-phthalocyanie catalysts in alkaline solutions［J］. J Phys Chem C, 2009, 113（48）: 20689-20697.
［15］BAKER R, WILKINSON D P, ZHANG J. Electrocatalytic activity and stability of substituted iron phthalocyanines towards oxygen reduction evaluated at different temperatures［J］. Electrochimica Acta, 2008, 53(23): 6906-6019.
［16］DE LILE J R, ZHOU Su. A density functional theory investigation of charge mobility in titanyl-phthalocyanines and their tailored peripherally substituted complexes［J］. ChemXpress, 2016, 9(5): 105.
［17］TANAKA A A, FIERRO C, SCHERSON D A, et al. Oxygen reduction on adsorbed iron tetrapyridinoporphyrazine［J］. Materials Chemistry and Physics, 1989, 22 (3/4): 431-456.
［18］BECK F. The redox mechanism of the chelate-catalysed oxygen cathode［J］. Journal of Applied Electrochemistry, 1977, 7(3): 239-245.
［19］SUN S, JIANG N, XIA D. Density functional theory study of the oxygen reduction reaction on metalloporphyrins and meallophthalocyanines［J］. Journal of Physical Chemistry C, 2011, 115(19): 9511-9517.
［20］ZAGAL J H. Handbook of fuel cells: Advances in electrocatalysis, materials, diagnostics and durability ［M］. Hoboken, NJ: Wiley, 2003, 544.
［21］SHI Zheng, ZHANG Jiujun. Density functional theory study of transitional metal macrocyclic complexes’ dioxygen-binding abilities and their catalytic activities toward oxygen reduction reaction［J］. J Chem Phys C, 2007, 111(1): 7084-7090.
［22］SHA Y, YU T H, MERINOV B V, et al. Oxygen hydration mechanism for the oxygen reduction reaction at Pt and Pd fuel cell catalysts［J］. Journal of Physical Chemistry Letters, 2011, 2（6）: 572-576.
