Stepwise Toward Pure Blue Organic Light-Emitting Diodes by Synergetically Locking and Shielding Carbonyl/Nitrogen-Based MR-TADF Emitters.

Deep-blue multi-resonance (MR) emitters with stable and narrow full-width-at-half-maximum (FWHM) are of great importance for widening the color gamut of organic light-emitting diodes (OLEDs). However, most planar MR emitters are vulnerable to intermolecular interactions from both the host and guest, causing spectral broadening and exciton quenching in thin films. Their emission in the solid state is environmentally sensitive, and the color purity is often inferior to that in solutions. Herein, a molecular design strategy is presented that simultaneously narrows the FWHM and suppresses intermolecular interactions by combining intramolecular locking and peripheral shielding within a carbonyl/nitrogen-based MR core. Intramolecularly locking carbonyl/nitrogen-based bears narrower emission of 2,10-dimethyl-12,12-diphenyl-4H-benzo[9,1]quinolizino[3,4,5,6,7-defg]acridine-4,8(12H)-dione in solution and further with peripheral-shielding groups, deep-blue emitter (12,12-diphenyl-2,10-bis(9-phenyl-9H-fluoren-9-yl)-4H-benzo[9,1]quinolizino[3,4,5,6,7-defg]acridine-4,8(12H)-dione, DPQAO-F) exhibits ultra-pure emission with narrow FWHM (c.a., 24 nm) with minimal variations (∆FWHM ≤ 3 nm) from solution to thin films over a wide doping range. An OLED based on DPQAO-F presents a maximum external quantum efficiency (EQEmax) of 19.9% and color index of (0.134, 0.118). Furthermore, the hyper-device of DPQAO-F exhibits a record-high EQEmax of 32.7% in the deep-blue region, representing the first example of carbonyl/nitrogen-based OLED that can concurrently achieve narrow bandwidth in the deep-blue region and a high electroluminescent efficiency surpassing 30%.

Retinal Adaptation in Response to Light and Dark Regimes in the Oriental Armyworm Mythimna separata (Lepidoptera: Noctuidae).

The oriental armyworm, Mythimna separata (Walker), is a well-known nocturnal migratory pest that relies on its exceptional nocturnal vision for navigation during long-distance flights. In this study, we investigated the ultrastructure of the compound eyes of adult M. separata using transmission electron microscopy and quantitatively evaluated adaptational changes in the retina under light and dark conditions. The compound eyes of M. separata are superposition eyes with a clear zone. The retina shows remarkable anatomical differences under light and dark adaptation, primarily characterized by distinct patterns of rhabdoms within the clear zone: the rhabdoms are nearly absent under light adaptation, but become more voluminous under dark adaptation. In the distal, middle, and proximal sections of the clear zone, the cross-sectional areas of retinulae and rhabdoms, as well as the rhabdom occupation ratio, are significantly larger under dark adaptation than under light adaptation. Conversely, the opposite trend is observed beneath the clear zone. These results indicate remarkable plasticity in the M. separata retina throughout a normal daily cycle, providing a theoretical basis for improving searchlight and ground light trap techniques for the management of this migratory species.

Thiyl Radical Trapped by Cobalt Catalysis: An Approach to Markovnikov Thiol-Ene Reaction.

In the presence of a thiyl radical species, the catalytic Markovnikov thiol-ene reaction is challenging because it prefers to proceed via a radical pathway, thereby leading to anti-Markovnikov selectivity. In this work, a rare example of thiyl radical engaged in Markovnikov thiol-ene reaction enabled by cobalt catalysis is reported. This protocol features the avoidance of unique oxidants, exclusive regioselectivity, and broad substrate scope. Scalable synthesis and late-stage modification of complex molecules demonstrate the practicability of the protocol.

Molecular Engineering of Perylene Diimide Polymers with a Robust Built-in Electric Field for Enhanced Solar-Driven Water Splitting.

The built-in electric field of the polymer semiconductors could be regulated by the dipole moment of its building blocks, thereby promoting the separation of photogenerated carriers and achieving efficient solar-driven water splitting. Herein, three perylene diimide (PDI) polymers, namely oPDI, mPDI and pPDI, are synthesized with different phenylenediamine linkers. Notably, the energy level structure, light-harvesting efficiency, and photogenerated carrier separation and migration of polymers are regulated by the orientation of PDI unit. Among them, oPDI enables a large dipole moment and robust built-in electric field, resulting in enhanced solar-driven water splitting performance. Under simulated sunlight irradiation, oPDI exhibits the highest photocurrent of 115.1 µA cm-2 for photoelectrochemical oxygen evolution, which is 11.5 times that of mPDI, 26.8 times that of pPDI and 104.6 times that of its counterparts PDI monomer at the same conditions. This work provides a strategy for designing polymers by regulating the orientation of structural units to construct efficient solar energy conversion systems.

Ultramorphology of the proboscis and sensilla of the Asian corn borer Ostrinia furnacalis (Lepidoptera: Crambidae).

The Asian corn borer, Ostrinia furnacalis (Guenée), is one of the most destructive lepidopteran pests affecting maize in Asia. Previous research on the feeding behavior of O. furnacalis has mostly focused on larvae, but the adult feeding preference has been unclear hitherto. In this study, we investigated the ultramorphology of the proboscis and sensilla of O. furnacalis using scanning electron microscopy and made morphological comparisons between the sexes, attempting to make predictions on the food preference and feeding behavior of the adults. The proboscis of O. furnacalis is divided into zones 1 and 2 with three types of sensilla, namely chaetica, basiconica, and styloconica. The entire proboscis and zone 2 of the females are significantly longer than those of the males. The main sexual difference in the sensilla is shown in the number of sensilla styloconica, which are eight in females but nine in males. The feeding preference of adult O. furnacalis is discussed based on the morphology of the proboscis and sensilla.

[Clinical phenotype characteristics and genetic analysis in children with nephronophthisis and related syndromes caused by different gene mutations]. / ä¸åŒåŸºå› çªå˜è‡´è‚¾å•ä½è‚¾ç—¨åŠç›¸å ³ç»¼åˆå¾æ‚£å„¿ä¸´åºŠè¡¨åž‹ç‰¹ç‚¹åŠåŸºå› åˆ†æž.

OBJECTIVES: To improve the understanding of the clinical phenotypes and genetic characteristics of nephronophthisis (NPHP) and related syndromes in children. METHODS: A retrospective analysis was performed on the medical data of eight children with NPHP and related syndromes who were diagnosed and treated in the Department of Pediatrics of the Second Hospital of Hebei Medical University, from January 2018 to November 2022. The clinical characteristics and genetic testing results were analyzed. RESULTS: Among these eight children, there were five boys and three girls, with an age of onset ranging from 15 months to 12 years. All 8 children exhibited different degrees of renal function abnormalities when they attended the hospital. Among the eight children, two had the initial symptom of delayed development, two had the initial symptom of anemia, and two were found to have abnormal renal function during physical examination. The extrarenal manifestations included cardiovascular abnormalities in two children, skeletal dysplasia in two children, liver dysfunction in one child, retinitis pigmentosa in one child, and visceral translocation in one child. All eight children had renal structural changes on ultrasound, and four children had mild to moderate proteinuria based on routine urine test. Of all eight children, five had NPHP1 gene mutations and one each had a gene mutation in the NPHP3, IFT140, and TTC21B genes, and four new mutation sites were discovered. CONCLUSIONS: Children with NPHP and related syndromes often have the initial symptom of delayed development or anemia, and some children also have extrarenal manifestations. NPHP and related syndromes should be considered for children with unexplained renal dysfunction, and high-throughput sequencing may help to make a confirmed diagnosis.

Nitrogen-doped carbon dots for efficient deep-blue light-emitting diodes with CIE closely approaching the HDTV standard color Rec.BT.709.

Here, we demonstrate deep-blue carbon dots (CDs) with luminescence centered at 415 nm and PLQY exceeding 60% via nitrogen doping. A bright and high-color-purity CDs-based light-emitting diode (CLED) is achieved with an external quantum efficiency (EQE) of 1.74%, a maximum luminance of 1155.0 cd m-2, and a colour coordinate (0.16, 0.08) closely approaching the HDTV standard color Rec.BT.709 (0.15, 0.06) specification.

Interface-Engineered Ni-Coated CdTe Heterojunction Photocathode for Enhanced Photoelectrochemical Hydrogen Evolution.

Photoelectrochemical (PEC) water splitting for hydrogen production using the CdTe photocathode has attracted much interest due to its excellent sunlight absorption property and energy band structure. This work presents a study of engineered interfacial energetics of CdTe photocathodes by deposition of CdS, TiO2, and Ni layers. A heterostructure CdTe/CdS/TiO2/Ni photocathode was fabricated by depositing a 100-nm n-type CdS layer on a p-type CdTe surface, with 50 nm TiO2 as a protective layer and a 10 nm Ni layer as a co-catalyst. The CdTe/CdS/TiO2/Ni photocathode exhibits a high photocurrent density (Jph) of 8.16 mA/cm2 at 0 V versus reversible hydrogen electrode (VRHE) and a positive-shifted onset potential (Eonset) of 0.70 VRHE for PEC hydrogen evolution under 100 mW/cm2 AM1.5G illumination. We further demonstrate that the CdTe/CdS p-n junction promotes the separation of photogenerated carriers, the TiO2 layer protects the electrode from corrosion, and the Ni catalyst improves the charge transfer across the electrode/electrolyte interface. This work provides new insights for designing noble metal-free photocathodes toward solar hydrogen development.

Minisci reaction of heteroarenes and unactivated C(sp3)-H alkanes via a photogenerated chlorine radical.

Here, an efficient Minisci reaction of heteroarenes and unactivated C(sp3)-H alkanes was achieved using an inexpensive FeCl3 as a photocatalyst. The photogenerated chlorine radical contributed to the HAT of C-H and subsequently initiated this reaction. Surprisingly, salt water and even seawater can act as a chlorine radical source, which provided an enlightening idea for future organic synthesis methods.

Ultrastructure of the dorsal ocellus of Bittacus planus larvae (Mecoptera: Bittacidae) with evolutionary significance.

The Bittacidae are unique in holometabolous insects in that their larvae bear a dorsal ocellus on the frons. The fine structure of the dorsal ocellus, however, has not been investigated to date. Here, the ultrastructure of the larval dorsal ocellus was studied in the hangingfly Bittacus planus Cheng, 1949 using light, scanning, and transmission electron microscopy. The dorsal ocellus of the larvae comprises a cornea, corneagenous cells, and retinula cells. The cornea is a laminated structure. A layer of corneagenous cells is located below the cornea. Numerous retinula cells are arranged tightly beneath the corneagenous cells. The retinula cells modify their adjacent membranes into numerous linear microvilli, which form an analogue of the rhabdom among adjacent retinula cells. The results show that the dorsal ocellus of larval Bittacidae is a highly vestigial organ and appears to be degenerating during the postembryonic development. The presence of the vestigial dorsal ocellus is likely to represent an ancestral plesiomorphy of holometabolous insects, providing new evidence for exploring the evolutionary origin of holometabolous larvae.

Phylogenetic implications based on an ultrastructural study with emphasis on the tracheal system of the compound eyes of three species of nymphalid butterflies.

Compound eyes are the prominent visual organs of insects and can provide valuable information for the reconstruction of insect phylogeny. Although the largest butterfly family (Nymphalidae) has been well defined, the infrafamilial phylogenetic relationships remain controversial hitherto. In the present study the ultrastructure of the compound eyes of three nymphalids Neptis beroe, Childrena zenobia, and Palaeonympha opalina was investigated using light and transmission electron microscopy in an attempt to seek potentially important phylogenetic characters. The compound eyes of the nymphalids share a tracheal system in a "1-4-8" branching pattern. The eight tracheal subbranches exhibit distinct distribution patterns along the basal retinula cell as follows: the tracheal subbranches of Palaeonympha opaline are close to the rhabdom in the distance from the distalmost part of the basal retinula cell to the rhabdom end, while those of N. beroe and C. zenobia are on the periphery of the retinula along almost the whole basal retinula cell and become close to the rhabdom just at the proximal end of the basal retinula cell. The tracheal structure of the three nymphalids is discussed for their potential phylogenetic implications.

On-Site Assessment of a Cryogenic Disinfectant for the Alpine Environment and Outer Packaging of Frozen Items / 生物医学与环境科学（英文）

OBJECTIVE@#To study the effectiveness and feasibility of cryogenic disinfectants in different cold scenarios and analyze the key points of on-site cryogenic disinfection.@*METHODS@#Qingdao and Suifenhe were selected as application sites for the manual or mechanical spraying of cryogenic disinfectants. The same amount of disinfectant (3,000 mg/L) was applied on cold chain food packaging, cold chain containers, transport vehicles, alpine environments, and article surfaces. The killing log value of the cryogenic disinfectant against the indicator microorganisms ( Staphylococcus aureus and Escherichia coli) was used to evaluate the on-site disinfection effect.@*RESULTS@#When using 3,000 mg/L with an action time of 10 min on the ground in alpine regions, the surface of frozen items, cold-chain containers, and cold chain food packaging in supermarkets, all external surfaces were successfully disinfected, with a pass rate of 100%. The disinfection pass rates for cold chain food packaging and cold chain transport vehicles of centralized supervised warehouses and food processing enterprises were 12.5% (15/120), 81.67% (49/60), and 93.33% (14/15), respectively; yet, the surfaces were not fully sprayed.@*CONCLUSION@#Cryogenic disinfectants are effective in disinfecting alpine environments and the outer packaging of frozen items. The application of cryogenic disinfectants should be regulated to ensure that they cover all surfaces of the disinfected object, thus ensuring effective cryogenic disinfection.

Clinical Study of Cytomegalovirus Infection after Allogeneic Hematopoietic Stem Cell Transplantation / 中国实验血液学杂志

OBJECTIVE@#To explore the risk factors of cytomegalovirus (CMV) and refractory CMV infection (RCI) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and their influences on survival.@*METHODS@#A total of 246 patients who received allo-HSCT from 2015 to 2020 were divided into CMV group (n=67) and non-CMV group (n=179) according to whether they had CMV infection. Patients with CMV infection were further divided into RCI group (n=18) and non-RCI group (n=49) according to whether they had RCI. The risk factors of CMV infection and RCI were analyzed, and the diagnostic significance of Logistics regression model was verified by ROC curve. The differences of overall survival (OS) and progression-free survival (PFS) between groups and the risk factors affecting OS were analyzed.@*RESULTS@#For patients with CMV infection, the median time of the first CMV infection was 48(7-183) days after allo-HSCT, and the median duration was 21 (7-158) days. Older age, EB viremia and gradeⅡ-Ⅳacute graft-versus-host disease (aGVHD) significantly increased the risk of CMV infection (P=0.032, <0.001 and 0.037, respectively). Risk factors for RCI were EB viremia and the peak value of CMV-DNA at diagnosis≥1×104 copies/ml (P=0.039 and 0.006, respectively). White blood cell (WBC)≥4×109/L at 14 days after transplantation was a protective factor for CMV infection and RCI (P=0.013 and 0.014, respectively). The OS rate in CMV group was significantly lower than that in non-CMV group (P=0.033), and also significantly lower in RCI group than that in non-RCI group (P=0.043). Hematopoietic reconstruction was a favorable factor for OS (P<0.001), whereas CMV-DNA≥1.0×104 copies/ml within 60 days after transplantation was a risk factor for OS (P=0.005).@*CONCLUSION@#The late recovery of WBC and the combination of EB viremia after transplantation are common risk factors for CMV infection and RCI. CMV-DNA load of 1×104 copies/ml is an important threshold, higher than which is associated with higher RCI and lower OS risk.

Clinical Analysis of Matched Sibling Donor Allogeneic Hematopoietic Stem Cell Transplantation in the Treatment of Young Patients with Multiple Myeloma / 中国实验血液学杂志

OBJECTIVE@#To investigate the efficacy and safety of matched sibling donor allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the treatment of young patients with multiple myeloma (MM).@*METHODS@#The clinical data of 8 young patients (median age：46 years) with MM who underwent allo-HSCT from HLA-indentical sibling donors in the First Affiliated Hospital of Chongqing Medical University from June 2013 to September 2021 were collected, and their survival and prognosis were retrospectively analyzed.@*RESULTS@#All the patients were successfully transplanted, and 7 patients could be evaluated the efficacy after transplantation. The median follow-up time was 35.2 (2.5-84.70) months. The complete response (CR) rate was 2/8 before transplantation and 6/7 after transplantation. Acute GVHD developed in 2 cases and extensive chronic GVHD developed in 1 case. Within 100 days, 1 case died of non-recurrent events, and 1-year and 2-year disease-free survival were 6 and 5 cases, respectively. At the end of follow-up, all the 5 patients who survived for more than 2 years survived, and the longest disease-free survival time has reached 84 months.@*CONCLUSION@#With the development of new drugs, HLA-matched sibling donor allo-HSCT may be a curable treatment for young patients with MM.

Effect and mechanism investigation on improving kidney deficient in mice of Polygoni Multiflori Radix Praeparata based on plasma metabolomics / 药学学报

Plasma nontargeted metabolomics technology was developed for investigating the effect and mechanism of improving kidney deficient in mice of Polygoni Multiflori Radix Praeparata. Thirty-five ICR mice were randomly divided into the control group, the model group, the BB24 h (braising with black bean sauce for 24 hours) group, the BB32 h group, and the BB40 h group. Biochemical indices in blood plasma of mice were measured by collecting eye blood after modeling. Changes in plasma endogenous metabolites of mice from each group were determined by ultra-performance liquid chromatography-linear trap quadrupole-orbitrap XL (UPLC-LTQ-orbitrap XL), and differential metabolites were screened. The results of pharmacodynamic investigation showed that compared to the model group, the levels of estradiol increased obviously in the BB24 h (P < 0.05), and the levels of cortisol increased obviously in BB32 h (P < 0.05). The hormone level of mice with kidney deficiency was significantly improved after taking processed Polygonum multiflorum. A total of 70 differential endogenous metabolites in blood plasma of mice were identified from all treatment groups, which mainly involved glycerophospholipid meta-bolism, arachidonic acid metabolism, phenylalanine metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, and linoleic acid metabolism. The study indicated that Polygoni Multiflori Radix Praeparata may play the role of tonifying liver and kidney by improving the disorder of hypothalamic-pituitary-adrenal axis and regulating lipid metabolism in mice. Correlation analysis on differential metabolites in blood plasma and the chemical constituents showed that stilbene glycosides and saccharides may be the key pharmacodynamic material basis. The present study provides a new reference and theoretical foundation for revealing the potential pharmacodynamic material basis and mechanism investigation on tonifying liver and kidney of Polygoni Multiflori Radix Praeparata. This study was carried out following the ethical guidelines and regulations for the use of laboratory animals of the Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences and passed the animal experimental ethical review [No. SYXK (Jing) 2019-0003].

Effectiveness and security of anisodine hydrobromide tablets in treating nonarteritic anterior ischemic optic neuropathy: a Chinese multicenter nonrandomized controlled study / 中华实验眼科杂志

Objective:To evaluate the efficacy and safety of oral anisodine hydrobromide tablets in the treatment of nonarteritic anterior ischemic optic neuropathy (NAION).Methods:A multicenter nonrandomized controlled trial was conducted.A total of 282 acute NAION patients (282 eyes) were recruited from 16 hospitals in China from July 2020 to May 2021.Patients were divided into two groups according to treatment methods, which were control group (124 cases, 124 eyes) receiving regular treatment including citicoline sodium plus Ginkgo biloba leaf liquid extract or Ginkgo biloba leaf extract tablets plus mecobalamin, and experimental group (158 cases, 158 eyes) receiving treatment in control group plus oral anisodine hydrobromide tablets 1 mg, twice daily for 2 to 3 months.Best corrected visual acuity (BCVA), visual field index (VFI), peripapillary retinal nerve fiber layer (pRNFL) and radial peripapillary capillary vessel density (RPC) were assessed at 1, 2, 3, and 6 months after enrollment using the standard decimal visual acuity chart, 750i Humphery visual field analyzer, Cirrus HD-OCT 4000/Cirrus HD-OCT 5000, RTVue-XR optical coherence tomography respectively.The primary outcomes were BCVA and VFI, and the secondary outcomes were pRNFL, RPC, and the side effects during the follow-up.The study adhered to the Declaration of Helsinki.All patients were fully informed about the treatment and purpose of this study and voluntarily signed the informed consent form.The study protocol was approved by Chinese PLA General Hospital (No.S2020-021-01). Results:In all, 242 patients (242 eyes) completed the follow-up of BCVA, and 98 patients (98 eyes) completed the VFI follow-up.In terms of visual function, BCVA and VFI improved significantly over time in the two groups, and BCVA and VFI were better in experimental group than in control group at various follow-up time points (all at P<0.05). In terms of structure, pRNFL gradually decreased in both groups with the extension of treatment, and pRNFL was significanthy thinner in experimental group than in control group at various follow-up time points (all at P<0.05). There was no significant difference in RPC between the two groups at the last follow-up ( P>0.05). There were two cases with side effects and one case was discontinued due to side effects 25 days after enrollment. Conclusions:Oral anisodine hydrobromide can improve visual acuity and visual field in NAION and accelerate the regression of optic disc edema, with good safety.

Application and prospect of drug discrimination in field of drug abuse / 中国药理学通报

Drug discrimination is a behavioral pharmacological technique to study the discriminative stimulus effects of drug. Currently drug discrimination has been widely used in preclinical drug development of CNS drugs, the most extensive of which is psychodependent research in the field of drug abuse. This review describes in general the basic principles of drug discrimination, preliminarily elaborates on the relevant characteristics and applications of the subjective effects, time-course effect, stereo specificity, individual differences, and receptor mechanisms, and its development prospects for hallucinogens and cannabis drugs are also presented.

Clinical phenotype characteristics and genetic analysis in children with nephronophthisis and related syndromes caused by different gene mutations / 中国当代儿科杂志

OBJECTIVES@#To improve the understanding of the clinical phenotypes and genetic characteristics of nephronophthisis (NPHP) and related syndromes in children.@*METHODS@#A retrospective analysis was performed on the medical data of eight children with NPHP and related syndromes who were diagnosed and treated in the Department of Pediatrics of the Second Hospital of Hebei Medical University, from January 2018 to November 2022. The clinical characteristics and genetic testing results were analyzed.@*RESULTS@#Among these eight children, there were five boys and three girls, with an age of onset ranging from 15 months to 12 years. All 8 children exhibited different degrees of renal function abnormalities when they attended the hospital. Among the eight children, two had the initial symptom of delayed development, two had the initial symptom of anemia, and two were found to have abnormal renal function during physical examination. The extrarenal manifestations included cardiovascular abnormalities in two children, skeletal dysplasia in two children, liver dysfunction in one child, retinitis pigmentosa in one child, and visceral translocation in one child. All eight children had renal structural changes on ultrasound, and four children had mild to moderate proteinuria based on routine urine test. Of all eight children, five had NPHP1 gene mutations and one each had a gene mutation in the NPHP3, IFT140, and TTC21B genes, and four new mutation sites were discovered.@*CONCLUSIONS@#Children with NPHP and related syndromes often have the initial symptom of delayed development or anemia, and some children also have extrarenal manifestations. NPHP and related syndromes should be considered for children with unexplained renal dysfunction, and high-throughput sequencing may help to make a confirmed diagnosis.

Ultrastructure of Ejaculatory Ducts of Cerapanorpa nanwutaina and Furcatopanorpa longihypovalva (Mecoptera: Panorpidae).

The ultrastructure of the ejaculatory duct was investigated in the scorpionflies Cerapanorpa nanwutaina (Chou 1981) and Furcatopanorpa longihypovalva (Hua & Cai, 2009) (Mecoptera: Panorpidae) using light and transmission electron microscopy. The ejaculatory ducts of both species comprise a median duct and an accessory sac. The median duct consists of a basal lamina, a mono-layered epithelium, a subcuticular cavity, and an inner cuticle. The accessory sac contains a single layer of epithelium and a basal lamina. A muscular layer is present in the accessory sac of C. nanwutaina and in the median duct of F. longihypovalva. The epithelia in the median duct and the accessory sac are well developed, their cells containing numerous cisterns of rough endoplasmic reticulum, mitochondria, and microvilli. The secretions of the median duct are first extruded into the subcuticular cavity and then into the lumen through an inner cuticle, while the secretions of the accessory sac are discharged directly into the lumen. The ejaculatory duct of F. longihypovalva is longer and has thicker epithelium with more cell organelles and secretions than that of C. nanwutaina.

Enhanced Photoelectrochemical Water Splitting of Black Silicon Photoanode with pH-Dependent Copper-Bipyridine Catalysts.

Since the water oxidation half-reaction requires the transfer of multi-electrons and the formation of O-O bond, it's crucial to investigate the catalytic behaviours of semiconductor photoanodes. In this work, a bio-inspired copper-bipyridine catalyst of Cu(dcbpy) is decorated on the nanoporous Si photoanode (black Si, b-Si). Under AM1.5G illumination, the b-Si/Cu(dcbpy) photoanode exhibits a high photocurrent density of 6.31 mA cm-2 at 1.5 VRHE at pH 11.0, which is dramatically improved from the b-Si photoanode (1.03 mA cm-2 ) and f-Si photoanode (0.0087 mA cm-2 ). Mechanism studies demonstrate that b-Si/Cu(dcbpy) has improved light-harvesting, interfacial charge-transfer, and surface area for water splitting. More interestingly, b-Si/Cu(dcbpy) exhibits a pH-dependent water oxidation behaviour with a minimum Tafel slope of 241 mV/dec and the lowest overpotential of 0.19 V at pH 11.0, which is due to the monomer/dimer equilibrium of copper catalyst. At pH ∼11, the formation of dimeric hydroxyl-complex could form O-O bond through a redox isomerization (RI) mechanism, which decreases the required potential for water oxidation. This in-depth understanding of pH-dependent water oxidation catalyst brings insights into the design of dimer water oxidation catalysts and efficient photoanodes for solar energy conversion.