Ni/N-rGO催化苯酚选择性加氢制备环己酮性能

以自制氧化石墨(GO)为原料，尿素为氮源，通过水热法制备了氮掺杂还原氧化石墨烯(N-rGO)载体，采用浸渍法制得不同镍负载量Ni/N-rGO催化剂，采用N₂吸附-脱附、XRD、SEM等手段对Ni/N-rGO催化剂进行表征分析，考察催化剂制备条件(活性组分负载量、尿素添加量、H₂还原温度)和反应条件(反应温度、反应压力、反应时间)对Ni/N-rGO催化剂催化苯酚选择性加氢制备环己酮的影响。结果表明：在活性组分负载质量分数为20%、尿素/GO质量比为30、H₂还原温度为450 ℃的条件下制备的20%Ni/N-rGO催化剂具有较大的比表面积和适宜的孔结构，金属镍分散相对均匀；在反应温度为150 ℃、反应压力为0.4 MPa、反应时间为2.0 h、20%Ni/N-rGO催化剂/苯酚质量比为0.35的最佳条件下，苯酚转化率为91.93%，环己酮选择性为61.75%；20%Ni/N-rGO催化剂重复使用5次后催化性能下降较明显，苯酚转化率降至82.17%，环己酮选择性降至50.93%。

Catalytic Performance of Ni/N-rGO in Selective Hydrogenation of Phenol to Cyclohexanone

With self-made graphite oxide (GO) as raw material and urea as nitrogen source, N-doped reduced graphene oxide (N-rGO) carrier was prepared by hydrothermal method. Catalysts with different nickel loading Ni/N-rGO were prepared by impregnation method. The Ni/N-rGO catalysts were characterized by N₂ adsorption-desorption and XRD, SEM. The effects of catalyst preparation conditions (active component loading, addition of urea, H₂ reduction temperature) and reaction conditions (reaction temperature, reaction pressure, reaction time) on catalytic performance in the selective hydrogenation of phenol to cyclohexanone catalyzed by Ni/N-rGO catalysts were investigated. Results show that the conditions of active components loading mass fraction of 20%， urea/GO mass ratio of 30 and H₂ reduction temperature of 450 ℃, this 20%Ni/N-rGO catalyst has large specific surface area and suitable pore structure, and the metal nickel dispersion is relatively uniform. Under the optimum conditions of reaction temperature of 150 ℃, reaction pressure of 0.4 MPa， reaction time of 2.0 h, 20%Ni/N-rGO catalyst/phenol mass ratio of 0.35, the conversion rate of phenol is 91.93% and the selectivity of cyclohexanone is 61.75%, respectively. However, the catalytic performance of 20%Ni/N-rGO catalyst remarkably decreases after 5 times reuse, with phenol conversion and cyclohexanone selectivity decreasing to 82.17% and 50.93% respectively.