The KCaSrTa5O15 photocatalyst with tungsten bronze structure for water splitting and CO2 reduction
The KCaSrTa5O15 photocatalyst with tungsten bronze structure for water splitting and CO2 reduction
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DOI：
10.1039/c4cp03892d
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发表时间：
2014-01-01
影响因子：
3.3
通讯作者：
Kudo, Akihiko
中科院分区：
文献类型：
--
作者：
Takayama, Tomoaki;Tanabe, Kentaro;Kudo, Akihiko
KCaSrTa 5 O 15具有钨青铜结构，带隙为4.1 eV，在没有助催化剂的情况下表现出水裂解活性。通过负载NiO助催化剂提高了催化剂的活性。优化后的NiO负载KCaSrTa 5 O 15在254 nm处的水分解表观量子产率为2.3%。当CO2气体鼓泡到反应物的水溶液中，Ag助催化剂负载KCaSrTa 5 O 15产生CO和H-2作为CO2和H2O的还原产物，分别，和O2作为H2O的氧化产物。利用（CO2）-C-13确定了CO的碳源为CO2分子。由产物（CO、H-2和O-2）的量计算得到的电子数与空穴数之比几乎为1。另外，CO生成所消耗的电子的转换数与作为CO2还原活性部位的助催化剂的Ag原子总数的比率在20小时时为8.6。这些结果表明，水消耗作为电子供体的这种光催化CO2还原在水性介质中。因此，具有钨青铜结构的KCaSrTa 5 O 15已经作为一种新的光催化剂而出现，该光催化剂利用水作为电子供体对水分解和CO2还原具有活性。
KCaSrTa5O15 with tungsten bronze structure and a band gap of 4.1 eV showed activity for water splitting without cocatalysts. The activity was improved by loading the NiO cocatalyst. The apparent quantum yield of optimized NiO-loaded KCaSrTa5O15 was 2.3% at 254 nm for water splitting. When CO2 gas was bubbled into the reactant aqueous solution, Ag cocatalyst-loaded KCaSrTa5O15 produced CO and H-2 as reduction products of CO2 and H2O, respectively, and O2 as an oxidation product of H2O. The carbon source of CO was confirmed to be CO2 molecules by using (CO2)-C-13. The ratio of the number of electrons to that of holes calculated from the amounts of products (CO, H-2 and O-2) was almost unity. Additionally, the ratio of the turnover number of electrons consumed for CO production to the total number of an Ag atom of the cocatalyst that was the active site for CO2 reduction was 8.6 at 20 h. These results indicate that water was consumed as an electron donor for this photocatalytic CO2 reduction in an aqueous medium. Thus, KCaSrTa5O15 with tungsten bronze structure has arisen as a new photocatalyst that is active for water splitting and CO2 reduction utilizing water as an electron donor.