Influence of particle size and shape on the rate of hydrogen produced by Al‐doped SrTiO 3 photocatalysts
Influence of particle size and shape on the rate of hydrogen produced by Al‐doped SrTiO 3 photocatalysts
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DOI：
10.1111/jace.18488
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发表时间：
2022-04
影响因子：
3.9
通讯作者：
Mingyi Zhang;P. Salvador;G. Rohrer
中科院分区：
文献类型：
--
作者：
Mingyi Zhang;P. Salvador;G. Rohrer
利用高通量、平行化和自动化的光化学反应装置，测量了不同形状和尺寸的掺铝钛酸锶的光催化产氢速率。结果表明，晶体形状对光催化活性有一定的影响，比表面积比在1.3~1.8之间的晶体比其他比例的晶体产氢更多。在相同条件下，{1 1 0}/{1 0 0}比表面积比为1.8的晶体在5 5 0µmolh−1 g−1(PH 7)下产生氢气，而只露出{1 0 0}面的晶体在3 0 0µmolh−1 g−1下产生氢气。表面积比可能在{110}表面上的光阳极反应和{100}表面上的光阴极反应之间提供了适当的平衡。在2 5 0-4 5 0 nm范围内，较大的晶体在pH 7时以4 0 0µmolh−1 g−1的速率产生氢气，而较小的晶体只产生2 0 0µmolh−1 g−1，这表明较大的晶体减缓了电子-空穴复合或反向反应的速度，晶体内的空间电荷宽度与粒子半径相当。
Photocatalytic hydrogen production rates have been measured from Al-doped SrTiO 3 with a range of controlled shapes and sizes using a high-throughput parallelized and automated photochemical reactor. It is found that the photocatalytic reactivity is influenced by crystal shape and that crystals with a {1 1 0} to {1 0 0} surface area ratio between 1.3 and 1.8 yield more H 2 than crystals with other ratios. Crystals with a {1 1 0}/{1 0 0} surface area ratio of 1.8 generate hydrogen at 550 µ mol h − 1 g − 1 at pH 7, whereas crystals with only {1 0 0} facets exposed generate hydrogen at 300 µ mol h − 1 g − 1 under the same condition. It is likely that the surface area ratio provides the appropriate balance between the pho-toanodic reaction on the {1 1 0} surface and the photocathodic reaction on the {1 0 0} surface. In the size range of 250–450 nm, larger crystals produce hydrogen at a rate of 400 µ mol h − 1 g − 1 at pH 7, whereas smaller crystals only produce 200 µ mol h − 1 g − 1 , suggesting that the larger crystals reduce the rate of electron– hole recombination or back reaction and that the widths of the space charges within the crystal are comparable to the particle radius.