CAJ | 학술논문

采用水热法合成了纳米棒状La(OH)3载体,通过湿式浸渍方法制备了10%Ni/La(Ⅲ)负载型催化剂,考察了500~800℃不同焙烧温度对于催化剂氢解山梨醇制备低碳二元醇的影响,结合XRD、SEM/EDS、BET、H2-TPR-MS、CO/CO2-TPD-MS、TG和ICP-AES等表征手段对Ni/La(Ⅲ)催化剂的构效关系进行了分析。结果表明,Ni/La(Ⅲ)催化剂表现出高的氢解反应活性,在较低的焙烧温度下(500℃)催化剂主要以NiO/La2 O2 CO3结构形式存在。随着焙烧温度的升高,NiO/La2 O2 CO3逐渐向La2 NiO4-La2 O3进行转变。碱性是影响不同催化剂活性的决定因素,高的焙烧温度促进了催化剂中强碱性位的生成,显著提高了氢解反应活性,但对液体产物的选择性无明显影响,在220℃、4 MPa H2、1.5 h的条件下,山梨醇完全转化,低碳二元醇的产率可达到53%。低的焙烧温度则增加了催化剂的水热稳定性。催化剂的失活主要归结于活性金属粒子在水相反应中从载体表面脱落而发生团聚,降低氢解反应活性。
채용수열법합성료납미봉상La(OH)3재체,통과습식침지방법제비료10%Ni/La(Ⅲ)부재형최화제,고찰료500~800℃불동배소온도대우최화제경해산리순제비저탄이원순적영향,결합XRD、SEM/EDS、BET、H2-TPR-MS、CO/CO2-TPD-MS、TG화ICP-AES등표정수단대Ni/La(Ⅲ)최화제적구효관계진행료분석。결과표명,Ni/La(Ⅲ)최화제표현출고적경해반응활성,재교저적배소온도하(500℃)최화제주요이NiO/La2 O2 CO3결구형식존재。수착배소온도적승고,NiO/La2 O2 CO3축점향La2 NiO4-La2 O3진행전변。감성시영향불동최화제활성적결정인소,고적배소온도촉진료최화제중강감성위적생성,현저제고료경해반응활성,단대액체산물적선택성무명현영향,재220℃、4 MPa H2、1.5 h적조건하,산리순완전전화,저탄이원순적산솔가체도53%。저적배소온도칙증가료최화제적수열은정성。최화제적실활주요귀결우활성금속입자재수상반응중종재체표면탈락이발생단취,강저경해반응활성。
Nanorod-shaped La( OH) 3 support was prepared by hydrothermal method, over which the supported Ni/La( III) catalysts were obtained through wet impregnation method; the influence of calcination temperature on the performance of Ni/La ( III ) catalyst in the hydrogenolysis of sorbitol to low-carbon glycols was then investigated by means of XRD, SEM/EDS, BET, H2-TPR-MS, CO/CO2-TPD-MS, ICP-AES and TG. The results revealed that the Ni/La ( III ) catalysts are highly active for sorbitol hydrogenolysis; the yield of low-carbon glycols reaches 53% after reaction at 220 ℃ and 4 MPa H2 for 1. 5 h. The catalyst calcined at low temperature (500℃) is mainly in the form of NiO/La2 O2 CO3 , which may transform into La2 NiO4-La2 O3 with the increase of calcination temperature. The basicity is a crucial factor for the hydrogenolysis activity; high calcionation temperature may enhance the basicity of the catalysts and then improve their hydrogenolysis activity, whereas the calcination temperature has little effect on the products selectivity. However, NiO/La2 O2 CO3 exhibits better hydrothermal stability than La2 NiO4-La2 O3 for sorbitol hydrogenolysis. The deactivation of catalysts can be attributed to the separation of active Ni particles from the support and the agglomeration of the active species, which may reduce the amount of the active metal sites and destroy the catalyst structure.