ABSTRACT
Photoelectrochemical (PEC) carbon dioxide (CO2) reduction (CO2R) holds the potential to reduce the costs of solar fuel production by integrating CO2 utilization and light harvesting within one integrated device. However, the CO2R selectivity on the photocathode is limited by the lack of catalytic active sites and competition with the hydrogen evolution reaction. On the other hand, serious parasitic light absorption occurs on the front-side-illuminated photocathode due to the poor light transmittance of CO2R cocatalyst films, resulting in extremely low photocurrent density at the CO2R equilibrium potential. This paper describes the design and fabrication of a photocathode consisting of crystal phase-modulated Ag nanocrystal cocatalysts integrated on illumination-reaction decoupled heterojunction silicon (Si) substrate for the selective and efficient conversion of CO2. Ag nanocrystals containing unconventional hexagonal close-packed phases accelerate the charge transfer process in CO2R reaction, exhibiting excellent catalytic performance. Heterojunction Si substrate decouples light absorption from the CO2R catalyst layer, preventing the parasitic light absorption. The obtained photocathode exhibits a carbon monoxide (CO) Faradaic efficiency (FE) higher than 90% in a wide potential range, with the maximum FE reaching up to 97.4% at -0.2 V vs. reversible hydrogen electrode. At the CO2/CO equilibrium potential, a CO partial photocurrent density of -2.7 mA cm-2 with a CO FE of 96.5% is achieved in 0.1 M KHCO3 electrolyte on this photocathode, surpassing the expensive benchmark Au-based PEC CO2R system.
ABSTRACT
As a common cause of liver injury, hepatic ischemia/reperfusion injury (HIRI) happens in various clinical conditions including trauma, hepatectomy and liver transplantation. Since transcription factor Yin Yang 1 (YY1) was reported to be downregulated after ischemia/reperfusion (I/R) injury, we focused on YY1 to explore its function in HIRI by functional assays like Cell Counting Kit-8 (CCK-8) assays and flow cytometry assays. The RT-qPCR assay revealed that YY1 was downregulated in hepatocytes after I/R injury. The function assays disclosed that YY1 facilitated cell viability and proliferation, but hindered cell apoptosis in hepatocytes after I/R injury. Through mechanism assays including luciferase reporter assay, RIP and RNA pulldown assay, miR-186-5p was found to bind with YY1 and promote hepatocyte apoptosis by targeting YY1. Subsequently, we verified that small nucleolar RNA host gene 1 (SNHG1) could sponge miR-186-5p to upregulate YY1. Importantly, we figured out that YY1 had a positive regulation on SNHG1. Along the way, YY1 was identified as the upstream transcription factor for SNHG1. In conclusion, our study unveiled a novel competing endogenous RNA (ceRNA) pattern of SNHG1/miR-186-5p/YY1 positive feedback loop in hepatic I/R injury, which might provide new insight into prevention of HIRI during liver transplantation or hepatic surgery.