Transition metal oxides (TMOs) have attracted extensive research attentions as promising electrocatalytic materials. Despite low cost and high stability, the electrocatalytic activity of TMOs still cannot satisfy the requirements of applications. Inspired by kinetics, the design of hollow porous structure is considered as a promising strategy to achieve superior electrocatalytic performance. In this work, cubic NiO hollow porous architecture (NiO HPA) was constructed through coordinating etching and precipitating (CEP) principle followed by post calcination. Being employed to detect glucose, NiO HPA electrode exhibits outstanding electrocatalytic activity in terms of high sensitivity (1323 μA mM−1 cm−2) and low detection limit (0.32 μM). The excellent electrocatalytic activity can be ascribed to large specific surface area (SSA), ordered diffusion channels, and accelerated electron transfer rate derived from the unique hollow porous features. The results demonstrate that the NiO HPA could have practical applications in the design of nonenzymatic glucose sensors. The construction of hollow porous architecture provides an effective nanoengineering strategy for high-performance electrocatalysts.Electronic supplementary materialThe online version of this article (10.1186/s11671-017-2406-0) contains supplementary material, which is available to authorized users.

Rational design of cage-like structure is an effective method for the improvement of the capacitive performance of transition metal hydroxides. In this work, cubic Ni(OH)2 nanocages (Ni(OH)2 NCs) were constructed through a coordinating etching and precipitating (CEP) route. Ni(OH)2 NCs possess abundant active sites, sufficient diffusion channels, and accelerated electron transfer rate, which are beneficial for electrochemical kinetics. As a positive electrode for supercapacitors, the Ni(OH)2 NCs/Ni foam (NF) electrode presents a high specific capacitance of 539.8 F g−1 at 1 A g−1, which is much larger than that of broken Ni(OH)2 NCs/NF (Ni(OH)2 BNCs/NF, 87.3 F g−1 at 1 A g−1). In addition, the Ni(OH)2 NCs/NF electrode still retains 96.9% of its initial specific capacitance after 2000 cycles. The asymmetric supercapacitor (ASC) devices were assembled using Ni(OH)2 NCs/NF and activated carbon (AC)/NF as positive and negative electrodes, respectively. The ASC exhibits a higher energy density of 23.3 Wh kg−1 at a power density of 800 W kg−1 compared to Ni(OH)2 BNCs/NF (3 Wh kg−1 at 880 W kg−1). These results demonstrate that the Ni(OH)2 NCs/NF electrode presents potential applications in the field of energy storage. The design of cage-like structure paves an effective way to achieve high-performance electrode materials.Electronic supplementary materialThe online version of this article (10.1186/s11671-019-3096-6) contains supplementary material, which is available to authorized users.

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To overcome the identification challenge of low-abundance lysine acetylation (Kac), a novel approach based on a molecularly imprinted polymer (MIP) was developed to improve the extraction capacity of Kac peptides in real samples. Green deep eutectic solvents (DESs) were introduced and used as one of the synergistic functional monomers with zinc acrylate (ZnA). Glycine–glycine–alanine–lysine­(ac)–arginine (GGAKacR) was chosen as a template and N,N′-methylenbisacrylamide (MBAA) was used as a cross-linker. The obtained GGAKacR-MIP had excellent selectivity for the template with an imprinting factor (IF) of up to 21.4. The histone digest addition experiment demonstrated that GGAKacR-MIP could successfully extract GGAKacR from a complex sample. Finally, the application to the extraction of Kac peptides from mouse liver protein digestion was studied in detail. The number of Kac peptides and Kac proteins identified was 130 and 110, which were 3.71-fold and 3.93-fold higher than those of the untreated sample. In addition, the number of peptides and proteins identified after treatment increased from 5535 and 1092 to 17 149 and 4037 (3.10-fold and 3.70-fold, respectively). The results showed that the obtained MIP may provide an effective technical tool for the identification of Kac-modification and peptide fractionation, as well as a potential approach for simultaneously identifying post-translational-modified proteomic and proteomic information.

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