Flexible and Transparent Triboelectric Nanogenerators Based on Polyoxometalate-Modified Polydimethylsiloxane Composite Films for Harvesting Biomechanical Energy

As one of the important friction materials for the construction of high-efficiency triboelectric nanogenerators (TENGs), polydimethylsiloxane (PDMS) has the advantages of high flexibility and transparency. However, the performance of pristine PDMS-based TENGs is not high enough, which limits its practical application. Polyoxometalates (POMs), as a class of nanoscale cluster compounds, have a strong ability to capture electrons. Appropriate POM materials can not only build nanostructures on the surface of PDMS without affecting its flexibility and transparency but also improve its surface roughness and enhance the ability to store charges, thereby enhancing the performance of TENGs. In this study, PDMS is modified by two kinds of Dawson-type POMs, and two POMs-TENGs are further constructed, named W-TENG and Mo-TENG, respectively. Performance tests show that the Mo-TENG exhibits an output voltage of 30 V and an output current of 500 nA, which are three times and twice that of the pristine PDMS-based TENG, respectively. This enhancement is attributed to POMs dispersed in the PDMS, which increase surface potential, surface roughness, and electronegativity. Finally, the application potential of Mo-TENG in wearable self-powered devices is demonstrated. This study expands the range of applications for POMs and provides an efficient and cost-effective method for the commercial manufacture of biosensors and self-powered devices

Insights into Shape Selectivity and Acidity Control in NiO-Loaded Mesoporous SBA-15 Nanoreactors for Catalytic Conversion of Cellulose to 5‑Hydroxymethylfurfural

Facilitated isomerization of cellulose hydrolysis intermediate glucose without unexpected byproducts, which is the rate-determining step in the production of high-value-added biofuels, enables the efficient production of 5-hydroxymethylfurfural (5-HMF) from cellulose. In this work, considering the essential role of the acidity control and shape selectivity of a zeolite catalyst, a NiO-loaded mesoporous NiO/poly(vinyl pyrrolidone) (PVP)-phosphotungstic acid (HPA)@SBA-15 nanoreactor was prepared. This SBA-15 nanoreactor with a pore size of 5.47 nm reduced the concentration of byproducts formic acid (FA) and levulinic acid (LA) through shape selection for intermediates. Well-defined NiO nanoparticles (Ni-to-carrier mass ratio was 1:1) provided the NiO/PVP-HPA@SBA-15 nanoreactor a high Lewis acidity of 99.29 μmol g–1 for glucose catalytic isomerization, resulting in an increase in total reducing sugar (TRS) yield by 5 times. Such a nanoreactor remarkably improved the reaction efficiency of 5-HMF production from cellulose (a 5-HMF selectivity of 95.81%) in the 1-butyl-3-methylimidazolium chloride ([BMIM]Cl)/valerolactone (GVL) biphasic system

Effect of single factors on the extraction yields of AG and DHQ.

<p>(a) Effect of solid-liquid ratio on the extraction yields of AG and DHQ. (b) Effect of soaking time on the extraction yields of AG and DHQ. (c) Effect of extraction time on the extraction yields of AG and DHQ. (d) Effect of ultrasound power on the extraction yields of AG and DHQ.</p

HPLC-UV and LC-ESI-MS analysis of DHQ.

<p>(a) Chemical structure of DHQ. (b) HPLC-UV chromatogram of DHQ standard. (c) HPLC-UV chromatogram of Larch wood sample. (d) LC-ESI-MS chromatogram of DHQ.</p

Comparison of different extraction methods.

<p>Comparison of different extraction methods.</p

Technical analysis of pulp.

<p>Technical analysis of pulp.</p

Effect of ethanol volume fraction on precipitation yield of AG.

<p>Effect of ethanol volume fraction on precipitation yield of AG.</p

Experimental design matrix to screen important variables for extraction yields of AG and DHQ.

<p>Experimental design matrix to screen important variables for extraction yields of AG and DHQ.</p

Credibility analysis of the regression equations.

<p>Credibility analysis of the regression equations.</p

Response surfaces.

<p>(a) Response surface of the extraction yields of DHQ, <i>Y₁</i> = f(A,B). (b) Response surface of the extraction yields of DHQ, <i>Y₁</i> = f(A,C). (c) Response surface of the extraction yields of DHQ, <i>Y₁</i> = f(B,C). (d) Response surface of the extraction yields of AG, <i>Y₂</i> = f(A,B). (e) Response surface of the extraction yields of AG, <i>Y₂</i> = f(A,C). (f) Response surface of the extraction yields of AG, <i>Y₂</i> = f(B,C).</p