Enhanced photocatalytic H2-production activity of TiO2 using Ni(NO3)2 as an additive.
Enhanced photocatalytic H2-production activity of TiO2 using Ni(NO3)2 as an additive.
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DOI：
10.1039/c2cp43628k
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发表时间：
2013-07
期刊：
影响因子：
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通讯作者：
Wenguang Wang;Shengwei Liu;L. Nie;B. Cheng;Jiaguo Yu
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文献类型：
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作者：
Wenguang Wang;Shengwei Liu;L. Nie;B. Cheng;Jiaguo Yu
在此，我们首次报道了用德固赛P25 TiO2粉末（P25）从甲醇和Ni(NO3)2的混合水溶液中生产H2。探讨了Ni(NO3)2用量对TiO2光催化生成h2活性的影响。结果表明，在Ni(NO3)2的存在下，TiO2的光催化生成h2的活性显著增强。最佳的Ni(NO3)2用量(Ni（NO3)2与TiO2和Ni(NO3)2的摩尔比）为0.32 mol%，在365 nm处生成h2的速率为2547 μmol h(-1) g(-1)，量子效率（QE）为8.1%，是纯TiO2的135倍。这种高光催化生成h2的活性是由于Ni（2+）在TiO2表面的吸附。Ni(2+)/Ni的电势(Ni(2+) + 2e（-) = Ni， E(o) = -0.23 V）略低于锐钛矿TiO2的导带（CB） （-0.26 V），但高于H(+)/H2的还原电势(2H(+) + 2e(-) = H2， E(o) = -0.00 V)，有利于TiO2向Ni（2+）的电子转移和Ni（2+）还原为Ni(0)。金属Ni的作用是帮助电荷分离和作为H2生成的助催化剂，从而增强TiO2的光催化H2生成活性。
Herein, we for the first time report the production of H2 using Degussa P25 TiO2 powder (P25) from a mixed aqueous solution of methanol and Ni(NO3)2. The effect of the amount of Ni(NO3)2 on the photocatalytic H2-production activity of TiO2 was investigated and discussed. The results indicate that the photocatalytic H2-production activity of TiO2 is significantly enhanced in the presence of Ni(NO3)2. The optimal Ni(NO3)2 amount (the molar ratio of Ni(NO3)2 to TiO2 and Ni(NO3)2) was found to be 0.32 mol%, giving a H2-production rate of 2547 μmol h(-1) g(-1) with a quantum efficiency (QE) of 8.1% at 365 nm, exceeding that of pure TiO2 by 135 times. This high photocatalytic H2-production activity is due to the adsorption of Ni(2+) on the surface of TiO2. The potential of Ni(2+)/Ni (Ni(2+) + 2e(-) = Ni, E(o) = -0.23 V) is slightly lower than the conduction band (CB) of anatase TiO2 (-0.26 V), but higher than the reduction potential of H(+)/H2 (2H(+) + 2e(-) = H2, E(o) = -0.00 V), which favors electron transfer from TiO2 to Ni(2+) and reduction of Ni(2+) to Ni(0). The role of metallic Ni is to help charge separation and to act as a co-catalyst for H2 production, thus enhancing the photocatalytic H2-production activity of TiO2.