Professor Fujishima was born in 1942 in Tokyo. He received his Ph.D. in Applied Chemistry at the University of Tokyo in 1971. He taught at Kanagawa University for four years before moving to the University of Tokyo, where he became a Professor in 1986. In 2003, he retired from this position and took on the position of Chairman at the Kanagawa Academy of Science and Technology. On January 1, 2010 he became President of Tokyo University of Science. His main interests are in photocatalysis, photoelectrochemistry, and diamond electrochemistry. A paper on semiconductor photoelectrochemistry published in Nature by Fujishima and Honda in 1972 (Electrochemical Photolysis of Water at a Semiconductor Electrode; DOI: 10.1038/238037a0) led to the birth of two major disciplines, liquid junction solar cells and semiconductor-assisted photocatalysis. The concept of exciting TiO₂ semiconductors with UV-light to split water has now become the basis for modern solar fuels research. For more than 45 years Prof. Fujishima has led the efforts to investigate properties of TiO₂ and other semiconductor photocatalysts. The photocatalysis concepts that he has laid down in his work continue to energize young researchers today to further advance the fields of artificial photosynthesis and environmental remediation. He has also closely worked with industries to develop photocatalysis products. Many of these TiO₂-based photocatalyst products can now be seen in self-cleaning glass, antibacterial tiles, paints, and air purifiers. After his tenure at the University of Tokyo, Prof. Fujishima now serves as the President of the Tokyo University of Science. During the recent 21st Topical Meeting of the International Society for Electrochemistry, Szeged, Hungary (April 23–26, 2017) I had the opportunity to discuss his successful journey into photocatalysis research (Figure 1). The following conversation provides some insights into the visionary views of Prof. Akira Fujishima. Figure 1. With Prof. Akira Fujishima during the 21st Topical Meeting of the International Society for Electrochemistry, Szeged, Hungary. (Photo courtesy of P. Kamat). EL (ACS Energy Letters): How did you come up with idea to test TiO₂ as a photoactive semiconductor to split water during your seminal work published in 1972? AK: When I was a graduate student of the University of Tokyo, at first I followed the previous works using Ge, ZnO, CdS electrodes in aqueous solution. Of course, from these experiments I observed those semiconductor electrodes were unstable under irradiation (dissolution happened). Then I looked for stable semiconductors. I got information that Mr. Nakazumi (President of Single Crystal Manufacturing Company) was making TiO₂ rutile single crystal. I asked him directly for one, and then I got it in 1967. Soon using this crystal, I obtained oxygen evolution due to water photolysis. I reported the photoinduced oxidation of water to produce oxygen on a titanium dioxide electrode in Japanese in 1969 (Fujishima, A.; Honda, K.; Kikuchi S. Photosensitized Electrolytic Oxidation on TiO₂ Semiconductor Electrode. J. Chem. Soc. Japan1969, 72, 108, in Japanese). Without light, this reaction requires a large input energy. However, with energetic UV light shining on a TiO₂ surface, the input energy decreases drastically. In 1972, I reported with Prof. Honda the complete photoinduced splitting of water into hydrogen and oxygen at a doped rutile single crystal electrode (Fujishima, A.; Honda, K. Electrochemical Photolysis of Water at a Semiconductor Electrode. Nature1972, 238 (5358), 37–38). In 1975, we reported the sustained production of hydrogen gas in sunlight (Fujishima, A.; Kohayakawa, K.; Honda, K. Hydrogen Production under Sunlight with an Electrochemical Photocell. J. Electrochem. Soc.1975, 122, 1487–1489). EL: You were the pioneer in exploring various aspects of TiO₂ in photocatalysis. What led you to identify the strength of photocatalysis for environmental remediation so early? AK: At the beginning of 1980, I recognized that it was not easy to carry out highly efficient hydrogen evolution using TiO₂ electrodes. An irradiated TiO₂ surface, however, has very strong oxidation power. Therefore, we coated a thin film of TiO₂ on various materials like glass, tiles, and so on. We then demonstrated the effectiveness of illuminated TiO₂ surfaces in removing pollutants and bacteria from air, water, and solid surfaces. In addition, we discovered photoinduced hydrophilicity. This fact is also of great practical importance because it allows surfaces to be self-cleaning with rain or gentle irrigation, and glass to be antifogging and not to form water droplets, as well as self-cleaning. EL: What were some of the major challenges that you encountered in taking the laboratory work to industry for the development of commercial products? AK: About 30 years ago, I became a professor at the University of Tokyo. At that time, some top people from research units of big Japanese companies (TOTO, Daikin, Toshiba, Hitachi,...) visited me and asked to do collaborative work on photocatalysis. After several years many products (air cleaning systems, tiles, glasses, and so on) were commercialized. EL: It has been more than four decades since your work on water splitting first appeared. Despite rigorous effort, we still have not designed economically sustainable, practical devices for photocatalytic H₂ production. Can you identify major challenges in utilizing the principles of photocatalysis for solar fuels? AK: One mole of water (18 g/mol) has 6 × 10²³ molecules. This number is so big compared with the number of photons absorbed by the TiO₂ surface. Therefore, I think that a hybrid system of Si-solar cell and water electrolysis is one of the practical ways to address the challenges. EL: What are the new challenges in photocatalysis that young researchers could address to succeed in their career? AK: Photocatalysis of TiO₂ has very nice properties, especially its very strong oxidation power and super hydrophilicity. Still, additional fundamental research work is needed to make this process effective in many less-explored areas. For example, there is plenty of scope to extend the photocatalysis to agricultural approaches or medical applications. Views expressed in this Energy Focus are those of the author and not necessarily the views of the ACS. The author declares no competing financial interest. This article is cited by 3 publications. Figure 1. With Prof. Akira Fujishima during the 21st Topical Meeting of the International Society for Electrochemistry, Szeged, Hungary. (Photo courtesy of P. Kamat).

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与藤岛彰的对话

藤岛教授于1942年出生于东京。他获得了博士学位。1971年在东京大学获得应用化学博士学位。在转入东京大学（于1986年成为教授）之前，他在神奈川大学任教了四年。2003年，他从此职位退休，出任董事长一职。在神奈川科学技术学院。2010年1月1日，他成为东京科学大学的校长。他的主要兴趣是光催化，光电化学和金刚石电化学。《自然》杂志上发表的有关半导体光电化学的论文1972年由Fujishima和Honda提出（半导体电极上的水的电化学光解法； DOI：10.1038 / 238037a0）导致了两个主要学科的诞生：液体结太阳能电池和半导体辅助光催化。现在，用紫外线激发TiO ₂半导体以分解水的概念已成为现代太阳能燃料研究的基础。超过45年的藤岛教授一直致力于研究TiO ₂和其他半导体光催化剂的性能。他在工作中提出的光催化概念继续激励着当今的年轻研究人员，以进一步推动人工光合作用和环境修复领域的发展。他还与行业紧密合作，以开发光催化产品。这些TiO中的许多现在可以在自清洁玻璃，抗菌瓷砖，油漆和空气净化器中看到基于₂的光催化剂产品。在东京大学任职后，藤岛教授现在担任东京科学大学的校长。在最近的国际电化学学会第21届主题会议上，匈牙利塞格德（2017年4月23日至26日），我有机会讨论了他在光催化研究方面的成功历程（图1）。以下对话提供了对藤岛彰教授的远见卓识的一些见解。图1.在匈牙利塞格德举行的国际电化学学会第21届主题会议上，藤岛彰教授与他进行了会谈。（照片由P. Kamat提供）。EL（ACS能源快报）：您如何提出测试TiO _2的想法在1972年发表的开创性著作中作为光敏半导体来分解水？ AK：当我是东京大学的研究生时，起初我遵循先前的工作，即在水溶液中使用Ge，ZnO，CdS电极。当然，从这些实验中，我观察到那些半导体电极在辐照下是不稳定的（发生溶解）。然后我寻找稳定的半导体。我得到的消息是中晶先生（单晶制造公司总裁）正在制造TiO ₂金红石单晶。我直接问他一个，然后在1967年得到它。不久之后，使用这种晶体，由于水的光解作用，我析出了氧气。1969年，我在日本报道了水的光诱导氧化作用，从而在二氧化钛电极上产生氧气（Fujishima，A。； Honda，K。； Kikuchi S.在TiO ₂半导体电极上进行光敏电解氧化。J。Chem。Soc。Japan 1969）。，72、108（日语）。没有光，该反应需要大量的输入能量。但是，随着高能紫外线照射在TiO _2上在表面上，输入能量急剧下降。1972年，我向本田教授报告了在掺杂的金红石型单晶电极上将水完全光诱导分解为氢和氧的过程（Fujishima，A。； Honda，K。在半导体电极上对水进行电化学光解。《自然》1972年，第238页（ 5358），37–38）。在1975年，我们报道在阳光下（藤岛，A。; Kohayakawa，K。;本田，太阳光下K.制氢与电化学光电池的持续产生氢气。J.电化学会志1975年，122，1487年至1489年）。EL：您是探索TiO ₂各个方面的先驱在光催化中。是什么导致您这么早就确定了光催化在环境修复方面的优势？ AK： 1980年初，我认识到使用TiO ₂电极进行高效的氢气释放并不容易。然而，经照射的TiO ₂表面具有非常强的氧化能力。因此，我们在玻璃，瓷砖等各种材料上涂覆了TiO ₂薄膜。然后，我们证明了照明的TiO ₂的有效性去除空气，水和固体表面中的污染物和细菌的表面。另外，我们发现了光诱导的亲水性。这个事实也具有很大的实际意义，因为它可以使表面在雨水或温和灌溉下自清洁，并且玻璃可以防雾并且不形成水滴，并且可以自清洁。EL：在将实验室工作推向工业领域以开发商业产品时，您遇到了哪些主要挑战？ AK：大约30年前，我成为东京​​大学的教授。当时，一些日本大公司（TOTO，Daikin，东芝，日立等）的研究部门的高层拜访了我，并要求进行光催化方面的合作。几年后，许多产品（空气清洁系统，瓷砖，玻璃等）都商品化了。EL：自您的水分解工作首次出现以来已有40多年了。尽管付出了巨大的努力，但我们仍未设计出经济上可持续的实用设备用于光催化H _2的生产。您能否确定在利用光催化原理生产太阳能燃料方面面临的主要挑战？ AK：一摩尔水（18 g / mol）具有6×10 ²³分子。与被TiO ₂表面吸收的光子数量相比，该数量是如此之大。因此，我认为硅-太阳能电池和水电解的混合系统是应对挑战的实用方法之一。EL：年轻的研究人员可以解决光催化领域的新挑战以成功实现他们的职业生涯吗？ AK： TiO _2的光催化具有非常好的性能，特别是其非常强的氧化能力和超强的亲水性。但是，还需要进行其他基础研究工作，才能使此过程在许多未开发的领域中有效。例如，有很大的范围将光催化作用扩展到农业方法或医学应用。本“能源焦点”中表达的观点只是作者的观点，不一定是ACS的观点。作者声明没有任何竞争性的经济利益。这篇文章被3个出版物引用。图1.在匈牙利塞格德举行的国际电化学学会第21届主题会议上，藤岛彰（Akira Fujishima）教授与会。（照片由P. Kamat提供）。