Abstract：
Exsolution generates metal nanoparticles anchored within crystalline oxide supports, ensuring efficient exposure, uniform dispersion, and strong nanoparticle-perovskite interactions. Increased doping level in the perovskite is essential for further enhancing performance in renewable energy applications; however, this is constrained by limited surface exsolution, structural instability, and sluggish charge transfer. Here, hybrid composites are fabricated by vacuum-annealing a solution containing SrTiO3 photoanode and Co cocatalyst precursors for photoelectrochemical water-splitting. In situ transmission electron microscopy identifies uniform, high-density Co particles exsolving from amorphous SrTiO3 films, followed by film-crystallization at elevated temperatures. This unique process extracts entire Co dopants with complete structural stability, even at Co doping levels exceeding 30%, and upon air exposure, the Co particles embedded in the film oxidize to CoO, forming a Schottky junction at the interface. These conditions maximize photoelectrochemical activity and stability, surpassing those achieved by Co post-deposition and Co exsolution from crystalline oxides. Theoretical calculations demonstrate in the amorphous state, dopant─O bonds become weaker while Ti─O bonds remain strong, promoting selective exsolution. As expected from the calculations, nearly all of the 30% Fe dopants exsolve from SrTiO3 in an H2 environment, despite the strong Fe─O bond\'s low exsolution tendency. These analyses unravel the mechanisms driving the amorphous exsolution.
摘要：
Exsolution产生锚定在结晶氧化物载体内的金属纳米颗粒，确保有效曝光，均匀分散,和强烈的纳米粒子-钙钛矿相互作用。增加钙钛矿中的掺杂水平对于进一步提高可再生能源应用的性能至关重要；然而，这受到有限的表面解的限制，结构不稳定，和缓慢的电荷转移。这里,通过对包含SrTiO3光阳极和Co助催化剂前体的溶液进行真空退火来制备杂化复合材料，以进行光电化学水分解。原位透射电子显微镜鉴定均匀，从非晶SrTiO3薄膜中溶解出高密度Co颗粒，然后在高温下进行薄膜结晶。这种独特的过程提取整个Co掺杂剂，具有完全的结构稳定性，即使Co掺杂水平超过30%，暴露在空气中，嵌入薄膜中的Co颗粒氧化成CoO，在界面处形成肖特基结。这些条件最大限度地提高光电化学活性和稳定性，超越了通过Co后沉积和Co从晶体氧化物中溶解而实现的那些。理论计算表明，在非晶态，掺杂剂─O键变弱，而Ti─O键仍然很强，促进选择性溶出。正如从计算中预期的那样，在H2环境中，几乎所有的30%Fe掺杂剂都从SrTiO3中析出，尽管Fe-O键具有很强的低溶解倾向。这些分析揭示了驱动无定形溶液的机制。
