In spite of advantages of direct methanol fuel cells, low methanol oxidation reaction and fuel crossover from anode to cathode, there remains a challenge that inhibits it from being commercialized. Active electrocatalysts are in high demand to promote the methanol oxidation reaction. The methanol reached at the anode can be immediately reacted, and thus, less methanol to cross to the cathode. The performance of electrocatalysts can be significantly influenced by varying the concentration of precursor solution. Theoretically, concentrated precursor solution facilitates rapid nucleation and growth; diluted precursor solution causes slow nucleation and growth. Rapid nucleation and slow growth have positive effect on the size of electrocatalysts which plays a significant role in the catalytic performance. Upon the addition of appropriate concentration of graphene oxide, the graphene oxide was reported to have stabilizing effect towards the catalyst nanoparticles. This work synthesized reduced graphene oxide–supported palladium electrocatalysts at different concentrations (0.5, 1.0, 2.0, 3.0 and 4.0 mg mL−1) with fixed volume and mass ratio of reduced graphene oxide to palladium by microwave-assisted reduction method. Results showed that reduced graphene oxide–supported palladium synthesized at a concentration of 1.0 mg mL−1 gave the best methanol oxidation reactivity (405.37 mA mg−1) and largest electrochemical active surface area (83.57 m2 g−1).

中文翻译：

---

成核和生长控制的还原氧化石墨烯负载钯电催化剂用于甲醇氧化反应

尽管直接甲醇燃料电池具有甲醇氧化反应低和燃料从阳极到阴极的交叉等优点，但仍存在阻碍其商业化的挑战。对促进甲醇氧化反应的活性电催化剂有很高的需求。到达阳极的甲醇可以立即反应，因此穿过阴极的甲醇更少。改变前体溶液的浓度会显着影响电催化剂的性能。理论上，浓缩的前体溶液有利于快速成核和生长；稀释的前体溶液会导致成核和生长缓慢。快速成核和缓慢生长对电催化剂的尺寸有积极影响，这对催化性能起着重要作用。在添加适当浓度的氧化石墨烯后，据报道氧化石墨烯对催化剂纳米颗粒具有稳定作用。这项工作通过微波辅助还原法合成了不同浓度（0.5、1.0、2.0、3.0 和 4.0 mg mL-1）的还原氧化石墨烯负载钯电催化剂，还原氧化石墨烯与钯的体积和质量比固定。结果表明，以 1.0 mg mL-1 的浓度合成的还原氧化石墨烯负载的钯具有最佳的甲醇氧化反应性 (405.37 mA mg-1) 和最大的电化学活性表面积 (83.57 m2 g-1)。这项工作通过微波辅助还原法合成了不同浓度（0.5、1.0、2.0、3.0 和 4.0 mg mL-1）的还原氧化石墨烯负载钯电催化剂，还原氧化石墨烯与钯的体积和质量比固定。结果表明，以 1.0 mg mL-1 的浓度合成的还原氧化石墨烯负载的钯具有最佳的甲醇氧化反应性 (405.37 mA mg-1) 和最大的电化学活性表面积 (83.57 m2 g-1)。这项工作通过微波辅助还原法合成了不同浓度（0.5、1.0、2.0、3.0 和 4.0 mg mL-1）的还原氧化石墨烯负载钯电催化剂，还原氧化石墨烯与钯的体积和质量比固定。结果表明，以 1.0 mg mL-1 的浓度合成的还原氧化石墨烯负载的钯具有最佳的甲醇氧化反应性 (405.37 mA mg-1) 和最大的电化学活性表面积 (83.57 m2 g-1)。