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Despite the intensive focuses on developing Prussian blue analogues (PBAs) derived catalysts, the direct utilization of PBAs for electrochemical water splitting to produce oxygen and especially hydrogen sources has rarely been reported, because of lacking effective strategies to improve the active site density and electrical transport of PBAs. Herein, we resolve such challenges by constructing the cubic NiCo-PBA bricks assembled 2D nanowalls on Ni foam (NF) through a Ni(OH) 2 nanosheet confined template technique. A great amount of sites are generated along the borders of brick subunits, and the 2D feature supplies downscaled charge diffusion path and high accessible surface area. Therefore, NiCo-PBA/NF exhibits impressive water electrolysis activities, with low overpotentials of 200 and 62 mV at 10 mA cm−2 for oxygen evolution reaction and hydrogen evolution reaction, respectively. Moreover, the NiCo-PBA/NF coupled two-electrode system achieves a low cell potential of 1.49 V at 10 mA cm−2 for overall water splitting, which is even better than the noble metal based IrO 2 -Pt/C system. This contribution sheds light on boosting the catalytic activity of PBAs and metal-organic frameworks toward water splitting, sensors, and other energy-related applications. Image 1 • NiCo-PBA cubes built nanowalls are developed using Ni(OH) 2 nanosheets. • Showing excellent OER activity with 200 mV at 10 mA cm−2. • Ni atoms are active but Co atoms in [Co(CN) 6 ] are inactive during OER. • Demonstrating the impressive HER activity that is close to Pt/C. • Showing excellent bifunctionality for overall water splitting. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The design of combining photoanode with biocathode was proposed to develop a robust PEC immunosensor. • The TiO 2 -NTs/CIS(1:3)/CIS(1:40) photoanode has evident photocurrent response and good stability. • The PS@Ab 2 conjugates of the biocathode could significantly amplify the photocurrent signal. • The developed PEC immunosensor exhibited both of enhanced sensitivity and specificity. Abstract Highly sensitive and specific detection of biomarkers is of great importance for diagnosis and treatment of the related diseases or cancers. We herein developed a robust photoelectrochemical (PEC) immunosensor with enhanced sensitivity and specificity based on evident photocurrent output of the photoanode and significant signal amplification of the biocathode. Prostate specific antigen (PSA, Ag) was used as a target model to exhibit analytical performances of the designed PEC immunosensor. Two kinds of CuInS 2 quantum dots (CIS QDs) with different composition were modified on the TiO 2 nanotubes (TiO 2 -NTs) electrode to fabricate the photoanode. Due to the co-sensitization effect of the CIS QDs on TiO 2 -NTs, an evident photocurrent output was generated at the photoanode. For the biocathode, Au nanoparticles (AuNPs) and polydopamine (PDA) were modified in order on indium-tin oxide (ITO) electrode to immobilize capture PSA antibody (Ab 1). Carboxyl-modified polystyrene (PS) nanospheres were coated with secondary antibodies (Ab 2) to form PS@Ab 2 conjugates, which were used as signal amplifiers via the specific immunoreaction between Ag and Ab 2. Based on joint action of evident photocurrent output of the photoanode and significant signal amplification of the biocathode, the designed PEC immunosensor exhibited an ultralow detection limit of 3.4 fg/mL for target PSA detection. Meanwhile, it also showed an enhanced specificity owing to the separation of the photoanode and the biocathode. [ABSTRACT FROM AUTHOR]

Solid-state nanochannels have great potentials in the vibrant field of photoelectrochemical (PEC) bioanalysis. This work herein demonstrates the innovative use of DNA-decorated nanoporous anodic alumina (NAA) nanochannels for sensitive PEC bioanalysis of telomerase (TE) activity. Specifically, telomerase primer sequences (TS) were initially immobilized within the NAA nanochannels and then extended by TE in the presence of deoxyribonucleoside triphosphates (dNTPs). The as formed single-strand DNA was then directed to hybrid with many partially matched single-strand assisting DNA (aDNA), leading to the formation of multiple DNAzymes by the unmatched parts and the subsequent DNAzyme-stimulated biocatalytic precipitation (BCP) within the nanochannels. Because the inhibited signals of the photoelectrode could be correlated with TE-enabled TS extension, an innovative nanochannels PEC bioanalysis could be realized for probing TE activity. This work features the ingenious use of DNA-associated nanochannels for PEC bioanalysis of TE activity. Given the versatile functions of DNA molecules, the extension of this strategy easily allows for addressing numerous other targets of interest. Also, we envision this work could inspire more interest for the further development of nanochannels PEC bioanalysis. • An innovative PEC bioanalysis of telomerase activity was proposed based on solid-state nanochannels. • The AgIn 5 S 8 /TiO 2 /ITO photoelectrode exhibited evident photocurrent response and high stability. • Target-induced formation of multiple DNAzymes could evidently amplify the PEC detection signal. • This strategy could be extended easily for building nanochannels PEC bioanalysis toward other targets of interest. [ABSTRACT FROM AUTHOR]

[Display omitted] • Eco-friendly piperazine-based ionic liquids for extraction denitrogenation. • Clarification of denitrogenation mechanism by DFT and MD simulation. • [C 1 Pi][Lac] was completely renewable and reused for 4 times, still maintaining the great extraction denitrogenation performance. It is of great significance to develop sustainable denitrogenation technology due to the presence of nitrogen compounds in fuel oils which have serious impact on its quality. To avoid the problems of incomplete denitrogenation and harsh operating conditions associated with conventional hydrodenitrogenation (HDN) process. The extractive denitrogenation method was adopted with ionic liquids-based (ILs-based) materials as extractants in this work. Through an overall review comparison revealed that ILs-based extractants consisting of conventional imidazole-based cations and fluorine-containing anions were toxic and hazardous to the environment. Therefore, four eco-friendly piperazine-based ionic liquids (Pi-based ILs) were synthesized as denitrogenation extractants by one-step method. The performance of the synthesized IL extractants in removing pyrrole from oil was evaluated by removal efficiency (RE). The polarity of each molecule in the system and the interaction between ILs and pyrrole were also analyzed. The conformational relationship between the denitrogenation performance and the structure of the ILs was revealed. The results showed that eco-friendly 1-methyl-piperazine lactate ([C 1 Pi][Lac]) exhibited the highest RE among the four Pi-based ILs, with the RE of 95.90 % for pyrrole under the optimal denitrogenation conditions: m IL : m oil = 1, extraction temperature of 298.15 K, extraction time of 30 min, and standing time of 15 min. Then, the denitrogenation process was visual explored by the molecular dynamics (MD) simulation. In addition, [C 1 Pi][Lac] was regenerated and reused, which showed that the eco-friendly [C 1 Pi][Lac] could be completely regenerated and reused well. This study laid a solid foundation for the development of eco-friendly and sustainable denitrogenation process. [ABSTRACT FROM AUTHOR]

Highlights: [•] Mesoporous Co3O4 octahedra have been prepared with simple sol-gel method. [•] Porous structure buffers the volume change and shortens the diffusion path of Li+. [•] Anisotropy octahedral morphology guarantees structural stability. [•] It exhibits high capacity, superior capacity retention and excellent rate capability. [Copyright &y& Elsevier]

Developing novel catalysts with high efficiency and low cost for electrochemical hydrogen production is of great significance for sustainable energy applications. Herein, we present the exploratory research on nickel foam supported heterostructures of NiCo hydrogen carbonate (Ni 0.6 Co 0.4 (HCO 3) 2) with Pt nanoparticles on the surface for alkaline water hydrogen evolution reaction (HER). The heterogeneous engineering ensures effective synergism of moderate hydrogen adsorption energy, accelerated catalysis kinetics, improved active sites, and enhanced charge transfer, thus inducing excellent HER activity (56 mV at 10 mA cm−2 for geometric area and 15 mV at 10 mA cm−2 for electrochemical surface area) and stable durability. Notably, the mass activity of Pt in Pt–Ni 0.6 Co 0.4 (HCO 3) 2 is even higher than that of Pt/C. This study provides new insights into developing high-efficiency catalysts for hydrogen electrocatalysis, which also demonstrates that hydrogen carbonates are promising alternatives for electrochemical water splitting in addition to the widely focused transition metal hydroxides and oxides. • Ni 0.6 Co 0.4 (HCO 3) 2 is firstly hybridized with Pt for improved HER. • The electronic interaction moderates the hydrogen adsorption energy on Pt. • The intrinsic HER activity is activated. • Improved active sites density and enhanced charge transfer are acquired. • The mass activity of Pt in composite catalyst is higher than that of Pt/C. [ABSTRACT FROM AUTHOR]

• Heterostructure of Ru 2 P particles decorated Ni 2 P nanosheets is prepared. • Synergism induces accelerated kinetics and intrinsic activity. • Improved active sites density and enhanced charge transfer are obtained. • Showing robust activity and stability for HER in wide pH range. Lacking efficient and pH-universal catalysts is currently the main obstacle for the large-scale production of hydrogen through electrochemical water splitting. The hetero material of Ru 2 P nanoparticles and Ni 2 P nanosheets is constructed on carbon fiber cloth as pH-tolerant catalyst for hydrogen generation. The designed heterointerface provides synergism and structure advantages for improved intrinsic catalysis activity, more accessible active sites, and enhanced charge transfer for hydrogen evolution. The electrochemical measurements demonstrate the active hydrogen production properties, such as low overpotentials (46 mV, 47 mV, and 51 mV in 0.5 M H 2 SO 4 , 1 M KOH, and 1 M phosphate-buffered saline, respectively) at a current density of 10 mA cm−2, as well as rapid catalysis kinetics with small Tafel slopes and good stability. [ABSTRACT FROM AUTHOR]

An efficient but general strategy for antifouling photoelectrochemical cytosensor was proposed by introducing zwitterionic peptide. The cytosensor demonstrated the distinct merits of high sensitivity and low fouling in the biological media. • Zwitterionic peptide as antifouling material was first introduced in PEC biosensor. • The ITO/TiO 2 /ZnIn 2 S 4 electrode as PEC matrix had evident photocurrent response and good stability. • The PEC cytosensor exhibited high sensitivity and good antifouling capability in the biological media. • The application of antifouling biomaterials is a promising way to resist nonspecific adsorption or biofouling. Resulting from nonspecific adsorption or obvious biofouling, target detection in real biological media is a potential challenge for most of the biosensors. Herein, we first report an antifouling photoelectrochemical (PEC) cytosensor by using zwitterionic peptide. The typical cervical carcinoma Henrietta Lacks (HeLa) cell was chosen as a target model and the aptamer AS1411 was used as its recognition element. TiO 2 nanoparticles (NPs) and ZnIn 2 S 4 nanocrystals (NCs) were modified in order on a bare indium–tin oxide (ITO), forming ITO/TiO 2 /ZnIn 2 S 4 electrode as the PEC matrix to immobilize aptamer AS1411 and zwitterionic peptide. The fabricated PEC cytosensor exhibited a high sensitivity toward HeLa cell detection, with the detection limit of 34 cells/mL. Besides, owning to excellent antifouling property of the zwitterionic peptide, evidently reduced nonspecific adsorption of the cytosensor was realized in the biological media. [ABSTRACT FROM AUTHOR]