Pt/CNFs-rGO催化劑的制備及催化氧化甲醇的性能研究

鄭慧娟,李妙魚,韓高義,曹曉會,陳曉芳,谷永鑫

(山西大學 分子科學研究所 能量轉換與存儲材料山西省重點實驗室，山西 太原 030006)

Pt/CNFs-rGO催化劑的制備及催化氧化甲醇的性能研究

鄭慧娟,李妙魚,韓高義*,曹曉會,陳曉芳,谷永鑫

(山西大學 分子科學研究所 能量轉換與存儲材料山西省重點實驗室，山西 太原 030006)

利用改進的Hummers法制備氧化石墨烯(GO),采用靜電紡絲和熱處理結合的方法得到碳納米纖維(CNFs),并將其混合作為催化劑載體。然后,以乙二醇為還原劑,采用一步微波法還原H2PtCl6的同時將GO還原為還原氧化石墨烯(rGO),得到Pt/CNFs-rGO復合催化劑。酸性條件下,用循環(huán)伏安法和計時安培法研究Pt/CNFs-rGO在甲醇電化學氧化中的催化性能。結果表明,與Pt/CNFs、Pt/rGO和商用Pt/C催化劑相比,復合催化劑Pt/CNFs-rGO對甲醇氧化有較高的催化性能,且mrGO∶mCNFs=4∶3時Pt/CNFs-rGO的催化效果最佳。碳纖維的引入可以提高Pt/rGO催化氧化甲醇的性能,其原因為CNFs的引入有效改善了石墨烯片層間的堆疊,從而提高了Pt粒子的利用率。

靜電紡絲;碳納米纖維;石墨烯;Pt納米粒子;微波法;甲醇電化學氧化

0 引言

直接甲醇燃料電池(DMFCs)作為一種理想的綠色能量轉換裝置備受科學研究者的青睞。由于其具有理論能量密度高、操作溫度低、燃料易于儲存和運輸以及對環(huán)境無污染等優(yōu)點,在便攜式電子設備和交通工具等領域具有廣闊的應用前景[1-4]。DMFCs通常使用貴金屬鉑作為陽極催化劑,然而鉑的資源有限且費用昂貴;而且,甲醇電化學氧化過程中產生的含碳中間產物(CO等)易使催化劑中毒,使其催化氧化甲醇的能力降低,從而限制了其工業(yè)化發(fā)展。因此,當務之急是減少鉑的使用量,并提高其催化氧化甲醇的性能[5-7]。

研究表明,催化劑的催化性能不僅受催化劑粒子大小、形狀等影響,而且載體材料的結構及性質也影響催化劑的性能[8-9]。碳材料因其具有比表面積大、電導率高等特點是一種優(yōu)良的催化劑載體,利用碳納米管、碳納米纖維(CNFs)、石墨烯、介孔碳微球等新型碳材料作載體,一方面可以顯著提高催化劑的性能,另一方面也可以減少鉑的用量達到降低成本的目的[8,10-13]。

石墨烯(Graphene)是一種具有單原子層厚度的新型碳材料,其獨特的二維結構和電子特性使其具有良好的物理、化學和機械性能,在很多領域有潛在的應用價值[14-15]。研究表明,以石墨烯為載體能提高Pt電催化氧化甲醇的活性[16-17]。盡管石墨烯具有較大的比表面積,但以石墨烯為載體負載電催化劑時,石墨烯片層在較強的范德華力和π-π相互作用力下容易發(fā)生堆疊,使其可有效利用的比表面積減小而導致負載貴金屬催化劑的活性位點減少,并且石墨烯片層的堆疊會阻礙反應物和產物的擴散,從而使催化劑的催化性能降低[18-20]。因此,可以通過加入其它碳材料使石墨烯片層間距離增大,改善石墨烯片層堆疊以利于反應物和產物的擴散[20-21]。

研究表明,電紡碳納米纖維(ES-CNF)膜作支撐電極可以大大提高商用催化劑的催化性能;利用ES-CNF膜制備的甲醇電化學氧化電極與商用催化劑相比,不僅具有較大的催化活性,還具有較高的穩(wěn)定性[2, 22]。微波法是近年來發(fā)展起來的一種快速高效制備催化劑的方法,由于其快速、均勻、有效的加熱使該法制備得到的催化劑納米顆粒粒徑小,分布均勻[23],是一種理想的催化劑制備方法。

因此,本文用靜電紡絲技術和改進的Hummers法分別制備CNFs和氧化石墨烯(GO),然后以乙二醇為還原劑,采用一步微波法還原H2PtCl6的同時將GO還原為還原氧化石墨烯(rGO),制備Pt/CNFs-rGO復合催化劑,來改善催化劑Pt/rGO催化氧化甲醇的性能。

1 實驗部分

1.1 主要試劑與儀器

聚丙烯腈(PAN,Mw=80 000)和Nafion溶液(質量濃度5%)購于Aldrich。商用Pt/C(Hispec 4100,質量分數(shù)40%)購于Johnson Matthey。石墨(325目)購于天津市光復精細化工研究所。商用碳紙(CP,HCP-020P,厚190 μm)購于Ballard。過硫酸鉀(K2S2O8)、過氧化氫(H2O2)、五氧化二磷(P2O5)、硝酸鈉(NaNO3)、高錳酸鉀(KMnO4)、N,N-二甲基甲酰胺(DMF)、濃硫酸(H2SO4)、濃鹽酸(HCl)、氯鉑酸(H2PtCl6·6H2O)、乙二醇(EG)、無水乙醇(C2H5OH)、無水甲醇(CH3OH)為分析純試劑,用前未經進一步提純處理。

DW-P403-4AC高壓直流電源、馬弗爐、SRJK-2-13管式電爐、微波合成萃取系統(tǒng)、JEOL-JSM-2010透射電子顯微鏡(200 kV)、JEOL-JSM-6700F場發(fā)射掃描電子顯微鏡、CHI660C(上海辰華)電化學工作站。

1.2 實驗方法

1.2.1 碳納米纖維(CNFs)的制備

利用靜電紡絲技術和高溫熱處理技術[22]相結合的方法構建導電CNFs。

1.2.2 氧化石墨烯(GO)的制備

以325目石墨為原料,采用改進的Hummers法[18]制備GO,在水中經超聲分散得到GO水溶液(8.7 mg/mL)。

1.2.3 催化劑Pt/CNFs-rGO、Pt/CNFs和Pt/rGO的制備

以H2PtCl6·6H2O為催化劑前驅體,EG為還原劑,應用微波加熱還原法制備復合催化劑Pt/CNFs-rGO。具體制備過程如下:稱取一定量的CNFs,加入EG超聲使其分散均勻,再加入一定量的GO水溶液(使mrGO∶mCNFs分別為4∶1，4∶2，4∶3和4∶4),繼續(xù)超聲使其混合均勻;然后,將該混合溶液和33.5 μL的H2PtCl6(0.19 mol/L)水溶液加入EG中,使制備過程中EG的總量為50 mL;攪拌均勻后將混合液置于微波反應器中,在600 W下加熱到160℃反應15 min;待溶液冷卻至室溫后,用3 mol/L的HCl溶液調節(jié)pH約為2,繼續(xù)攪拌12 h;最后,抽濾并用蒸餾水洗滌,得催化劑Pt/CNFs-rGO。

用同樣的方法制備催化劑Pt/CNFs和Pt/rGO,且上述所有催化劑中金屬Pt含量均為30%。

1.2.4 電極Pt/CNFs-rGO-CP、Pt/CNFs-CP和Pt/rGO-CP的構建

將CP切成10 mm×2.0 mm的矩形條作為電極載體,采用滴涂法構建Pt/CNFs-rGO-CP、Pt/CNFs-CP和Pt/rGO-CP電極。具體過程為:分別稱取4.17 mg的Pt/CNFs-rGO、Pt/CNFs和Pt/rGO催化劑(含1.25 mg Pt)于1 mL水中,并加入0.25 mL Nafion溶液(質量濃度5%),將上述混合溶液超聲分散均勻,取5 μL滴于CP表面(面積約為4 mm2,分兩次滴涂),室溫下完全干燥后得電極Pt/CNFs-rGO-CP、Pt/CNFs-CP和Pt/rGO-CP。其中,電極負載的Pt量為0.125 mg·cm-2。

1.2.5 電化學性能測試

應用兩室三電極法在CHI660C 電化學工作站測試電極對甲醇的催化氧化性能。測試中,構建的電極、飽和甘汞電極(SCE)和鉑網(wǎng)分別作為工作電極、參比電極和對電極。電解液為0.5 mol/L H2SO4+1.0 mol/L CH3OH水溶液,測試溫度為25±1℃;而且,在測試電化學性能前,先用高純氮氣除去電解液中溶解的氧氣,并且在整個實驗過程中保證氮氣持續(xù)通過電解液表面。

2 結果與討論

2.1 催化劑Pt/rGO、Pt/CNFs和Pt/CNFs-rGO的結構表征

由rGO的透射電鏡圖(圖1A)可以看出,rGO為透明的片狀結構,其表面存在大量的褶皺,這些褶皺有利于金屬納米粒子的負載[24]。圖1B是催化劑Pt/rGO的透射電鏡圖,從圖中可以看出,Pt納米粒子均勻地分散在rGO表面,平均粒徑為2.5 nm。圖1C為靜電紡絲技術和高溫熱處理技術相結合制備的CNFs的透射電鏡圖(插圖是CNFs的掃描電鏡圖),由圖可見,CNFs表面較光滑,平均直徑約為150 nm;而且,從插圖中可以發(fā)現(xiàn),CNFs相互交錯形成許多三維孔隙結構,這些結構不僅有利于催化劑的分散而且有助于反應物在電化學反應過程中的擴散。圖1D是Pt/CNFs的透射電鏡圖,由圖可知,Pt納米粒子均勻地分散在CNFs表面,平均粒徑約為5.3 nm;而且,負載Pt粒子后CNFs表面變得粗糙。對比圖1B和1D可以發(fā)現(xiàn),Pt納米粒子在rGO表面分散地更均勻,粒徑較小,這是由于GO表面含有大量的含氧官能團,有利于Pt納米粒子的分散,而未經處理的CNFs表面含氧官能團較少的緣故。

圖2是催化劑Pt/CNFs-rGO 的透射電鏡圖,圖2A-D中rGO和CNFs的質量比依次為4∶1,4∶2,4∶3,4∶4。由圖可知,Pt粒子均勻地分散在rGO和CNFs表面,平均粒徑約為3.0 nm。從圖2A-D的插圖可以看出,CNFs的量依次增加,這與實驗過程中所加rGO和CNFs的比例相符;而且,CNFs均勻分散在rGO片層間,有效防止rGO片層的堆疊,有利于催化劑粒子活性位點的充分利用以及反應物質的擴散;此外,有的rGO片包裹在CNFs表面,使CNFs表面變得粗糙,利于Pt粒子的均勻分散。

Fig.2 TEM images of Pt/CNFs-rGO among which the mass ratio of mrGO to mCNFs is 4∶1 (A), 4∶2 (B), 4∶3 (C) and 4∶4 (D)圖2 催化劑Pt/CNFs-rGO的透射電鏡圖，mrGO∶mCNFs為(A)4∶1，(B)4∶2，(C)4∶3和(D)4∶4

2.2 Pt/rGO、Pt/CNFs和Pt/CNFs-rGO催化氧化甲醇的活性測定

表1 Pt/rGO、Pt/CNFs和Pt/CNFs-rGO催化氧化甲醇的催化性能對比Table 1 The catalytic activity of methanol oxidation on Pt/rGO, Pt/CNFs and Pt/CNFs-rGO

Fig.3 (A) Cyclic voltammetry (CV) curves obtained for methanol oxidation on CP (a),Pt/C-CP (b) and Pt/CFMs-CP (c) and (B) CV curves for methanol oxidation on Pt/rGO-CP(a) and Pt/CNFs-rGO-CP among which the mass ratio of mrGO to mCNFs is 4∶1 (b), 4∶2 (c), 4∶3 (d), 4∶4 (e)The electrolyte is 1.0 mol/L CH3OH + 0.5 mol/L H2SO4 solution.The scan rate is 50 mV s-1.圖3 (A)電極CP (a), Pt/C-CP (b)和Pt/CNFs-CP (c)催化氧化甲醇的循環(huán)伏安曲線；(B)電極Pt/rGO-CP (a)和Pt/CNFs-rGO-CP催化氧化甲醇的循環(huán)伏安曲線，其中mrGO∶mCNFs為4∶1 (b)，4∶2 (c)，4∶3 (d)，4∶4 (e)；電解液為1.0 mol/L CH3OH + 0.5 mol/L H2SO4水溶液，掃速為50 mV s-1

2.3 Pt/rGO、Pt/CNFs和Pt/CNFs-rGO催化氧化甲醇的穩(wěn)定性測定

圖4是甲醇在不同電極上發(fā)生催化氧化反應時,恒定電勢0.45 V時的計時安培曲線。圖4A是甲醇在電極Pt/CNFs-CP和Pt/C-CP上氧化時的計時安培曲線,從圖中可以看出,兩電極催化氧化甲醇的計時安培曲線變化趨勢類似,催化氧化甲醇的峰電流密度達到最大值后則隨著極化時間的延長而逐漸下降。極化1 000 s后,電極Pt/CNFs-CP和Pt/C-CP催化氧化甲醇的峰電流密度從最初的最大值15.10和9.85 mA·cm-2分別降至3.90和2.40 mA·cm-2,分別減少了約74.17%和75.63%,說明電極Pt/CNFs-CP的穩(wěn)定性略優(yōu)于電極Pt/C-CP。

圖4B是甲醇在電極Pt/rGO-CP和Pt/CNFs-rGO-CP上發(fā)生氧化時的計時安培曲線。如圖所示,不同電極催化氧化甲醇的電流密度隨時間變化的趨勢類似,均為達到最大值后隨極化時間的延長而逐漸減小。當mrGO∶mCNFs=4∶3時,甲醇在復合催化劑Pt/CNFs-rGO上發(fā)生氧化時的電流密度最大;而且,極化10 000 s后,剩余電流密度最大(1.99 mA·cm-2),減少了約92.57%(表2)。上述結果說明,與其他電極相比,Pt/CNFs-rGO (mrGO∶mCNFs=4∶3)具有較高的催化活性和較好的穩(wěn)定性。CNFs的引入使rGO片層間距離增大,改善了rGO的堆疊,使rGO表面的含氧活性基團暴露利于Pt的負載,提高Pt的抗毒化能力,最終提高催化劑的催化活性和穩(wěn)定性。

Fig.4 (A) Chronoamperometric (CA) curves of methanol electrooxidation on Pt/C-CP (a) and Pt/CNFs-CP (b) and (B) CA curves of methanol electrooxidation on Pt/rGO-CP(a) and Pt/CNFs-rGO-CP among which the mass ratio of mrGO to mCNFs is 4∶1 (b), 4∶2 (c), 4∶3 (d), 4∶4 (e) at 0.45 V. The electrolyte is 1.0 mol/L CH3OH + 0.5 mol/L H2SO4 aqueous solution圖4 (A)電極Pt/C-CP(a)和Pt/CNFs-CP(b)催化氧化甲醇的計時安培曲線；(B)電極Pt/rGO-CP(a)和Pt/CNFs-rGO-CP催化氧化甲醇的計時安培曲線，其中mrGO∶mCNFs=4∶1(b)，4∶2(c)，4∶3(d)，4∶4(e)電解液為1.0 mol/L CH3OH + 0.5 mol/L H2SO4水溶液，恒定電勢為0.45 V

表2 Pt/rGO、Pt/CNFs和Pt/CNFs-rGO催化氧化甲醇的穩(wěn)定性對比Table 2 Catalytic stability of methanol oxidation on Pt/rGO, Pt/CNFs and Pt/CNFs-rGO

3 結論

[1] Koenigsmann C,Wong S S.One-dimensional Noble Metal Electrocatalysts:A Promising Structural Paradigm for Direct Methanol Fuel Cells[J].EnergyEnvironSci,2011,4:1161-1176.DOI:10.1039/c0ee00197j.

[2] Li M Y,Han G Y,Yang B S,etal.Using Formic Acid Vapor as Reducer to Prepare Pt Nanoparticles Supported on Carbon Nanofiber Mats for Methanol Electrooxidation[J].CataCommun,2014,51:86-89.DOI:10.1016/j.catcom.2014.03.034.

[3] Sun J,Ma H F,Jiang H,etal.General Synthesis of Binary PtM and Ternary PtM1M2Alloy Nanoparticles on Graphene as Advanced Electrocatalysts for Methanol Oxidation[J].JMaterChemA,2015,3:15882-15888.DOI:10.1039/c5ta01613d.

[4] Guo J W,Zhao T S,Prabhuram J,etal.Development of PtRu-CeO2/C Anode Electrocatalyst for Direct Methanol Fuel Cells[J].JPowerSources,2006,156:345-354.DOI:10.1016/j.jpowsour.2005.05.093.

[5] Lv J J,Li S S,Zheng J N,etal.Facile Synthesis of Reduced Graphene Oxide Supported PtAg Nanoflowers and Their Enhanced Electrocatalytic Activity[J].IntJHydrogenEnergy,2014,39:3211-3218.DOI:10.1016/j.ijhydene.2013.12.112.

[6] Lin Z,Ji L W,Krause W E,etal.Synthesis and Electrocatalysis of 1-aminopyrene-functionalized Carbon Nanofiber-supported Platinum-ruthenium Nanoparticles[J].JPowerSources,2010,195:5520-5526.DOI:10.1016/j.jpowsour.2010.03.059.

[7] Wang C,Waje M,Wang X,etal.Proton Exchange Membrane Fuel Cells with Carbon Nanotube Based Electrodes[J].NanoLett,2004,4:345-348.DOI:10.1021/nl034952p.

[8] Xu M W,Gao G Y,Zhou W J,etal.Novel Pd/β-MnO2Nanotubes Composites as Catalysts for Methanol Oxidation in Alkaline Solution[J].JPowerSources,2008,175:217-220.DOI:10.1016/j.jpowsour.2007.09.069.

[9] Tsuji M,Kubokawa M,Yano R,etal.Fast Preparation of PtRu Catalysts Supported on Carbon Nanofibers by the Microwave-polyol Method and Their Application to Fuel Cells[J].Langmuir,2007,23:387-390.DOI:10.1021/la062223u.

[10] Yuan W Y,Cheng Y,Shen P K,etal.Significance of Wall Number on the Carbon Nanotube Support-promoted Electrocatalytic Activity of Pt NPs Towards Methanol/formic Acid Oxidation Reactions in Direct Alcohol Fuel Cells[J].JMaterChemA,2015,3:1961-1971.DOI:10.1039/c4ta04613g.

[11] Calderón J C,García G,Querejeta A,etal.Carbon Monoxide and Methanol Oxidations on Carbon Nanofibers Supported Pt-Ru Electrodes at Different Temperatures[J].ElectrochimActa,2015,186:359-368.DOI:10.1016/j.electacta.2015.09.121.

[12] Hao Y F,Wang X D,Zheng Y Y,etal.Size-controllable Synthesis of Ultrafine PtNi Nanoparticles Uniformly Deposited on Reduced Graphene Oxide as Advanced Anode Catalysts for Methanol Oxidation[J].IntJHydrogenEnergy,2016,41:9303-9311.DOI:10.1016/j.ijhydene.2016.04.093.

[13] Bruno M M,Viva F A,Agustina Petruccelli M,etal.Platinum Supported on Mesoporous Carbon as Cathode Catalyst for Direct Methanol Fuel Cells[J].JPowerSources,2015,278:458-463.DOI:10.1016/j.jpowsour.2014.12.097.

[14] Li D,Kaner R B.Graphene-Based Materials[J].Science,2008,320:1170-1171.DOI:10.1126/science.1158180.

[15] Zhao Y,Li X G,Zhou X,etal.Review on the Graphene Based Optical Fiber Chemical and Biological Sensors[J].SensorsandActuatorsB,2016,231:324-340.DOI:10.1016/j.snb.2016.03.026.

[16] Qian W,Hao R,Zhou J,etal.Exfoliated Graphene-supported Pt and Pt-based Alloys as Electrocatalysts for Direct Methanol Fuel Cells[J].Carbon,2013,52:595-604.DOI:10.1016/j.carbon.2012.10.031.

[17] Bin D,Ren F F,Wang H W,etal.Facile Synthesis of PVP-assisted PtRu/RGO Nanocomposites with High Electrocatalytic Performance for Methanol Oxidation[J].RSCAdv,2014,4:39612-39618.DOI:10.1039/c4ra07742c.

[18] Fu K,Wang Y,Mao L C,etal.Facile One-pot Synthesis of Graphene-porous Carbon Nanofibers Hybrid Support for Pt Nanoparticles with High Activity Towards Oxygen Reduction[J].ElectrochimActa,2016,215:427-434.DOI:10.1016/j.electacta.2016.08.111.

[19] Jiang L L,Fan Z J.Design of Advanced Porous Graphene Materials:from Graphene Nanomesh to 3D Architectures[J].Nanoscale,2014,6:1922-1945.DOI:10.1039/c3nr04555b.

[20] Wang H L,Kakade B A,Tamaki T,etal.Synthesis of 3D Graphite Oxide-exfoliated Carbon Nanotube Carbon Composite and Its Application as Catalyst Support for Fuel Cells[J].JPowerSources,2014,260:338-348.DOI:10.1016/j.jpowsour.2014.03.014.

[21] Vinayan B P,Ramaprabhu S.Platinum-TM (TM=Fe,Co) Alloy Nanoparticles Dispersed Nitrogen Doped (Reduced Graphene Oxidemultiwalled Carbon Nanotube)Hybrid Structure Cathode Electrocatalysts for High Performance PEMFC Applications[J].Nanoscale,2013,5:5109-5118.DOI:10.1039/c3nr00585b.

[22] Li M Y,Han G Y,Yang B S.Fabrication of the Catalytic Electrodes for Methanol Oxidation on Electrospinning-derived Carbon Fibrous Mats[J].ElectrochemCommun,2008,10:880-883.DOI:10.1016/j.elecom.2008.04.002.

[23] Rahsepar M,Kim H.Microwave-assisted Synthesis and Characterization of Bimetallic PtRu Alloy Nanoparticles Supported on Carbon Nanotubes[J].JAlloysCompd,2015,649:1323-1328.DOI:10.1016/j.jallcom.2015.07.224.

[24] Shao J J,Li Z J,Zhang C,etal.A Wavy Graphene/Platinum Hybrid with Increased Electroactivity for the Methanol Oxidation Reaction[J].JMaterChemA,2014,2:1940-1946.DOI:10.1039/c3ta14134a.

[25] Zhao G Y,Xu C L,Guo D J,etal.Template Preparation of Pt-Ru and Pt Nanowire Array Electrodes on a Ti/Si Substrate for Methanol Electro-oxidation[J].JPowerSources,2006,162:492-496.DOI:10.1016/j.jpowsour.2006.06.082.

[26] Zhang L J,Xia D G.Electrocatalytic Activity of Ordered Intermetallic PtSb for Methanol Electro-oxidation[J].ApplSurfSci,2006,252:2191-2195.DOI:10.1016/j.apsusc.2005.03.221.

[27] 李妙魚,韓高義,楊斌盛.Pt/CFMs電極的制備及其在甲醇電化學氧化中的性能研究[J].山西大學學報:自然科學版,2013,36(1):68-73.

[28] Sharma S,Ganguly A,Papakonstantinou P,etal.Rapid Microwave Synthesis of CO Tolerant Reduced Graphene Oxide-supported Platinum Electrocatalysts for Oxidation of Methanol[J].JPhysChemC,2010,114:19459-19466.DOI:10.1021/jp107872z.

[29] Gu H H,Huang Y P,Zuo L Z,etal.Graphene Sheets Wrapped Carbon Nanofibers as a Highly Conductive Three-dimensional Framework for Perpendicularly Anchoring of MoS2:Advanced Electrocatalysts for Hydrogen Evolution Reaction[J].ElectrochimActa,2016,219:604-613.DOI:10.1016/j.electacta.2016.10.015.

PlatinumNanoparticlesSupportedontheCompoundofCarbonNanofibersandReducedGrapheneOxideforMethanolElectrooxidation

ZHENG Huijuan,LI Miaoyu,HAN Gaoyi*,CAO Xiaohui,CHEN Xiaofang,GU Yongxin

(InstituteofMolecularScience,KeyLaboratoryofMaterialsforEnergyConversionandStorageofShanxiProvince,ShanxiUniversity,Taiyuan030006,China)

Graphite oxide (GO) was synthesized by the improved Hummers’ method. Carbon nanofibers (CNFs) were fabricated by combining the electrospinning and thermally treating. Then Pt nanoparticles were supported on the compound of CNFs and reduced graphene oxide (rGO) by a one-pot microwave heating method using ethylene glycol as the reducer. The performance of Pt/CNFs-rGO toward methanol electrooxidation was investigated by cyclic voltammetry and chronoamperometry methods in acidic electrolyte solutions. The results demonstrate that Pt/CNFs-rGO exhibits higher electrocatalytic performance toward methanol oxidation than Pt/CNFs, Pt/rGO and commercial Pt/C. The introduction of CNFs could enhance the electrocatalytic performance of Pt/rGO toward methanol oxidation. When the mass ratio ofmrGOtomCNFsis 4∶3, the electrode of Pt/CNFs-rGO shows the best catalytic performance for methanol oxidation. The reason may be that the introduction of CNFs into the structure of rGO can avoid the stacking of graphene sheets effectively and improve the utilization of Pt nanoparticles.

electrospinning;carbon nanofibers;graphene;Pt nanoparticles;microwave synthesis;methanol electrooxidation

10.13451/j.cnki.shanxi.univ(nat.sci.).2017.04.021

2016-11-18；

2017-01-03

國家自然科學基金 (21574076;21501113;21407100);山西省自然科學基金(2012021021-3; 2014011016-1)

鄭慧娟(1990-),女,山西洪洞人,碩士研究生。E-mail:861143372@qq.com

*通信作者：韓高義(HAN Gaoyi),E-mail:han_gaoyis@sxu.edu.cn

O643.3

A

0253-2395(2017)04-0830-08