Water-assisted preparation of Ni/La(OH)3 catalyst for efficient catalytic C-O bond hydrogenolysis of tetrahydrofuran-dimethanol

Abstract

Due to easy dehydration of La(OH)₃ to LaOOH by thermal treatment, it is challenging to prepare highly efficient Ni/La(OH)₃ catalyst for hydrogenolysis reactions. Herein, Ni/La(OH)₃ (Ni/La-2) catalyst is prepared by thermal reduction of NiO/La(OH)₃ in hydrogen flow with vaporized water, while La(OH)₃ is partially dehydrated to LaOOH without water vapor affording Ni/(La(OH)₃ + LaOOH) (Ni/La-1). Ni/La-2 displays 93 % and 3 % yields of 1,2,6-hexanetriol (HTO) and 1,6-hexanediol (HDO) respectively towards C-O hydrogenolysis of tetrahydrofuran-dimethanol (THFDM) in batch reactor and high stability (200 h) in fixed-bed reactor, which is the best among the reported catalysts to the best of our knowledge. Ni/La-2 possesses pure La(OH)₃ as support, enhanced dispersion of Ni species and abundant Ni^δ+-O-La interfaces in comparison to Ni/La-1, which results in the exceptional catalytic performances in C-O hydrogenolysis of THFDM. A fine control of reaction temperature and time is required to optimize the yields HTO and HDO in hydrogenolysis of THFDM over Ni/La-2. The water-assisted preparation method provides a new perspective for the preparation of La(OH)₃ supported metal catalysts.