New simple La‐Ni complexes as efficient precursors for functional LaNiO3‐based ceramics

Abstract

AbstractPerovskite LaNiO3 is of immense significance in a range of fields such as heterogeneous catalysis. Herein, new convenient approach for preparing LaNiO3 via thermolysis of new simple complexes, [Ni (bpy)3] [La (NO3)5(MeCN)] (1, bpy is 2,2'‐bipyridine) and [Ni (phen)3] [La (NO3)5(H2O)]·2MeCN (2, phen is 1,10‐phenanthroline), is reported. These first examples of unambiguously characterized LaNiO3 precursors are chemically stable and can be synthesized rapidly in good yields. While virtually monophasic LaNiO3 can be prepared from 2 via only 3‐h annealing on air at 800°C, there are always minor admixtures in oxide samples prepared from 1. Peculiarities of intrinsic thermal transformations of 1 and 2 affecting such difference have been revealed. Thus, 1 and 2 are the first series of compositionally related heterometallic La‐Ni complexes studied as precursors for LaNiO3‐based ceramics. Comparatively high surface areas of LaNiO3‐based ceramics produced from 1 and 2 at 800°C determine its high catalytic activity towards dry reforming of methane (DRM) to syngas. Nearly quantitative CH4 and CO2 conversions as well as CO and H2 yields were achieved in 800–900°C range without preliminary reduction to Ni/La2O3 composites. Thus, LaNiO3‐based ceramics prepared from 1 and 2 are good precursors for in situ production of efficient catalysts for DRM.