Supporting information for

Electrocatalytic Oxidation of Volatile Organic Compounds at Gas-

Solid InterfacesBo Zhang1, Min Chen1,2, Lian Wang1, Xu Zhao1,2, Renzhi Hu2,3, Hao Chen3, Pinhua Xie2,3,4, Changbin Zhang1,2,*, Hong He1,2,4

1. State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.

2. University of Chinese Academy of Sciences, Beijing 100049, China.

3. State Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China.

4. Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.

**Corresponding author.

E-mail address: cbzhang@rcees.ac.cn (Changbin Zhang)

I. List of chemicals and reagents (All chemical reagents are of analytical grade)

Titanium foam plate (30 mm×2 mm) Kunshan TengErHui Electronic

Technology Co.,Ltd, China)

The size of particles used for building Ti foam was 3.0 mm.

SnCl4·5H2O, SbCl3, PtCl4 Aladdin Reagent Co., Ltd

ethanediol, isopropanol, n-butanol,benzene Alfa Aesar Chemical Co., Ltd

graphene oxide dispersion Nanjing XFNano Materials Tech Co. Ltd

carbon fiber paper TGP-H-090, Toray

Nafion-117 DuPont, USA

NH4Cl, HCl, ascorbic acid, NaF and HNO3Sinopharm Chemical Reagent Co.,Ltd

II. Experimental

Figure S1 schematic diagram of the gas-solid electrochemical reactor and the

membrane electrode assembly

III. Results

Figure S2 SEM images of (a) untreated Ti foam substrate (b) the etched Ti foam

substrate (c) Sb-doped SnO2 on Ti plate.

Figure S3 XRD patterns of Sb doped SnO2 supported on Ti foam (SS-28.7/Ti-foam)

and Ti plate (SS-28.7/Ti-plate).

Figure S4 XPS patterns of Sn and Sb 3d transition region of SS-28.7/Ti electrode.

Figure S5. SEM images of (a) CFP, (b) rGO, (c) Pt/rGO/CFP and (d) XRD patterns

The as-synthesized rGO/CFP and Pt/rGO/CFP electrodes are firstly characterized

by SEM analysis. Fig. S5a shows the smooth surface of the carbon fiber. The rGO

nanosheets formed on the carbon fibers appear as a flexible thin film with a number of

wrinkles (fig. S5b). The rGO sheets, providing a substrate for depositing Pt particles,

promoted particle agglomeration and growth (Fig. S5c), presumably owing to the

strong interaction between residual surface oxides and Pt ions. A nanosheet Pt

morphology was generated by the sp2 atomic carbon network. XRD patterns of the

CFP, rGO/CFP and Pt/rGO/CFP electrodes are shown in Fig. S5d. It can be seen that

the CFP diffraction peaks of rGO/CFP and Pt/rGO/CFP are weaker due to the coating

layer of rGO. Diffraction peaks assigned to (111), (200), (220) and (222) of metallic

Pt are observed for the Pt/rGO/CFP electrodes.

Figure S6 Repeated electro-oxidation cycles of gaseous 40 ppm benzene

Figure S7 Mineralization current efficiency versus time for the electro-

oxidation of gaseous 40 ppm benzene in all-solid cell.

Figure S8 SEM of SS-28.7/Ti post-electrolysis of benzene (on the left) XPS patterns

of C 1s region of freshly prepared (red line) and post-electrolysis (black line) SS-

28.7/Ti (on the right).

Figure S9 Time-profiled production of •OH radicals at E=2.0 V for SS-28.7/Ti in

water.

Figure S10 Time-profiled cathodic production of H2 and H2O2 at Pcell=1.0 V in all-

solid cell