Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA.
Nano Lett. 2012 Feb 8;12(2):1102-6. doi: 10.1021/nl2045588. Epub 2012 Jan 27.
Monodisperse CoPd nanoparticles (NPs) were synthesized and studied for catalytic formic acid (HCOOH) oxidation (FAO). The NPs were prepared by coreduction of Co(acac)(2) (acac = acetylacetonate) and PdBr(2) at 260 °C in oleylamine and trioctylphosphine, and their sizes (5-12 nm) and compositions (Co(10)Pd(90) to Co(60)Pd(40)) were controlled by heating ramp rate, metal salt concentration, or metal molar ratios. The 8 nm CoPd NPs were activated for HCOOH oxidation by a simple ethanol wash. In 0.1 M HClO(4) and 2 M HCOOH solution, their catalytic activities followed the trend of Co(50)Pd(50) > Co(60)Pd(40) > Co(10)Pd(90) > Pd. The Co(50)Pd(50) NPs had an oxidation peak at 0.4 V with a peak current density of 774 A/g(Pd). As a comparison, commercial Pd catalysts showed an oxidation peak at 0.75 V with peak current density of only 254 A/g(Pd). The synthesis procedure could also be extended to prepare CuPd NPs when Co(acac)(2) was replaced by Cu(ac)(2) (ac = acetate) in an otherwise identical condition. The CuPd NPs were less active catalysts than CoPd or even Pd for FAO in HClO(4) solution. The synthesis provides a general approach to Pd-based bimetallic NPs and will enable further investigation of Pd-based alloy NPs for electro-oxidation and other catalytic reactions.
单分散 CoPd 纳米粒子 (NPs) 被合成并用于催化甲酸 (HCOOH) 氧化 (FAO)。 NPs 通过 Co(acac)(2) (acac = 乙酰丙酮) 和 PdBr(2) 在 260°C 下在油胺和三辛基膦中的共还原制备，其尺寸 (5-12nm) 和组成 (Co(10)Pd(90) 至 Co(60)Pd(40)) 通过加热速率、金属盐浓度或金属摩尔比来控制。 8nm CoPd NPs 通过简单的乙醇洗涤进行 HCOOH 氧化活化。在 0.1M HClO(4)和 2M HCOOH 溶液中，它们的催化活性遵循 Co(50)Pd(50) > Co(60)Pd(40) > Co(10)Pd(90) > Pd 的趋势。 Co(50)Pd(50) NPs 在 0.4V 处具有氧化峰，峰电流密度为 774A/g(Pd)。相比之下，商业 Pd 催化剂在 0.75V 处显示出氧化峰，峰电流密度仅为 254A/g(Pd)。当 Co(acac)(2)用 Cu(ac)(2) (ac = 醋酸盐)代替时，该合成程序也可以扩展到制备 CuPd NPs，在其他条件相同的情况下。在 HClO(4)溶液中，CuPd NPs 作为 FAO 的催化剂，其活性比 CoPd 甚至 Pd 都低。该合成提供了一种制备 Pd 基双金属 NPs 的通用方法，并将促进对 Pd 基合金 NPs 在电氧化和其他催化反应中的进一步研究。
