The critical factors of photocatalytic H2 production from seawater by using TiO_(2)as photocatalyst  

作　　者：Yaqian He Pengfei Li Wenning Liu Li An Dan Qu Xiayan Wang Zaicheng Sun 

机构地区：[1]Beijing Key Laboratory for Green Catalysis and Separation,Center of Excellence for Environmental Safety and Biological Effects,Faculty of Environment and Life,Beijing University of Technology,Beijing 100124,China

出　　处：《Nano Research》2023年第4期4620-4624,共5页纳米研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.21872001,22272003,21805004,and 51801006);the Beijing Municipal High-Level Innovative Team Building Program(No.IDHT 20180504);Beijing Outstanding Young Scientists Program(No.BJJWZYJH0201910005017);Beijing Natural Science Foundation(Nos.KZ201710005002 and 2192005);Beijing Municipal Science and Natural Science Fund Project(No.KM201910005016);these funding agencies are acknowledged.

摘　　要：The solar H_(2)generation directly from natural seawater is a sustainable way of green energy.However,it is limited by a low H_(2)generation rate even compared to fresh water.In this report,TiO_(2)is chosen as a model photocatalyst to disclose the critical factor to deteriorate the H_(2)generation rate from seawater.The simulated seawater(SSW),which is composed of eight ions(Na^(+),K^(+),Ca^(2+),Mg^(2+),Cl^(−),Br^(−),SO_(4)^(2−),and CO_(3)^(2−)),is investigated the effect of each ion on the H_(2)production.The results indicate that all ions have a negative effect at the same concentration as in the seawater except Br−.The CO_(3)^(2−)has the most serious deterioration,and the H_(2)production rate lowers near 40%even at[CO_(3)^(2−)]of 1.5 mmol·L^(−1).The H_(2)production rate can be recovered to 85%if the CO_(3)^(2−)is excluded from the SSW.To understand the reason,the zeta potential of the TiO_(2)treated with different ions aqueous solution reveals that the zeta potential decreases when it is treated with CO_(3)^(2−)and SO_(4)^(2−)due to they can adsorb on the surface of TiO_(2)nanoparticles.Fourier transform infrared(FTIR)and thermogravimetric analysis-mass spectroscopy(TGA-MS)further confirm that the adsorbed ion is mainly from CO_(3)^(2−).Since the pH of seawater is about 8.9 between pKa1(6.37)and pKa2(10.3)of H_(2)CO3,the CO_(3)^(2−)should exist in the form of HCO3−in the seawater.We proposed a simple method to remove the adsorbed HCO3−from the TiO_(2)surface by adjusting the pH below the pKa1.The results indicate that if a trace amount of HCl(adjusting pH~6.0)is added to the SSW,the H_(2)production rate can be recovered to 85%of that in pure water.

关 键 词：seawater H_(2)production rate adsorb ions PH 

分 类 号：O643.36[理学—物理化学] O644.1[理学—化学]