Supported PdAu bimetallic nanoparticles have been developed for the direct synthesis of H2O2 (DSHP). However, to date, the dilute H2 streams necessary to avoid potential risks of explosion limits the attainable product concentrations of H2O2. Here, a series of silicon-modified Al2O3 (SixAl) were synthesized for loading PdAu bimetallic nanoparticles. The H2 consumption turnover frequency (TOF) and H2O2 formation TOF show a volcano trend with the silica content, where PdAu/Si5.6Al exhibits the best H2 consumption TOF and H2O2 formation TOF (11259.3 and 1995.2 h−1). Silica on the surface of Al2O3 is identified as Brønsted (B) acid site. The increase of B acid sites density accelerates the H2 conversion into H atoms, thereby boosting H2O2 formation process. The adsorption and dissociation of H2 into atomic H at B acid sites would spill across the support to PdAu nanoparticles reversely. The reversed hydrogen spillover effect induced by B acid site accounts for enhanced H2 conversion and H2O2 productivity for PdAu/SixAl.

中文翻译：

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布朗斯台德酸诱导的可逆氢气溢出加速过氧化氢的直接合成


已开发出负载型 PdAu 双金属纳米颗粒用于直接合成 H2O2 (DSHP)。然而，迄今为止，避免潜在爆炸风险所需的稀氢气流限制了可达到的 H2O2 产品浓度。在此，合成了一系列硅改性 Al2O3 (SixAl)，用于负载 PdAu 双金属纳米粒子。 H2消耗周转频率（TOF）和H2O2形成TOF随二氧化硅含量呈现火山趋势，其中PdAu/Si5.6Al表现出最佳的H2消耗TOF和H2O2形成TOF（11259.3和1995.2 h−1）。 Al2O3 表面的二氧化硅被确定为 Brønsted (B) 酸位。 B酸位密度的增加加速了H2转化为H原子，从而促进了H2O2的形成过程。 H2 在 B 酸位点吸附和​​解离成原子 H 会反向溢出到 PdAu 纳米颗粒的载体上。 B 酸位引起的反向氢溢出效应增强了 PdAu/SixAl 的 H2 转化率和 H2O2 生产率。