Pacchioni Gianfranco, Sicolo Sabrina, Valentin Cristiana Di, Chiesa Mario, Giamello Elio
Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via R. Cozzi, 53 - 20125, Milano, Italy.
J Am Chem Soc. 2008 Jul 9;130(27):8690-5. doi: 10.1021/ja710969t.
On the basis of experimental evidence and DFT calculations, we propose a simple yet viable way to stabilize and chemically activate gold nanoclusters on MgO. First the MgO surface is functionalized by creation of trapped electrons, (H (+))(e (-)) centers (exposure to atomic H or to H 2 under UV light, deposition of low amounts of alkali metals on partially hydroxylated surfaces, etc.); the second step consists in the self-aggregation of gold clusters deposited from the gas phase. The calculations show that the (H (+))(e (-)) centers act both as nucleation and activation sites. The process can lead to thermally stable gold cluster anions whose catalytic activity is enhanced by the presence of an excess electron.
基于实验证据和密度泛函理论计算，我们提出了一种简单且可行的方法来稳定并化学活化氧化镁上的金纳米团簇。首先，通过产生俘获电子、(H(+))(e(-))中心（暴露于原子氢或紫外光下的氢气中、在部分羟基化表面上沉积少量碱金属等）使氧化镁表面功能化；第二步是气相沉积的金团簇的自聚集。计算表明，(H(+))(e(-))中心既作为成核位点又作为活化位点。该过程可导致热稳定的金团簇阴离子，其催化活性因过量电子的存在而增强。
