In this paper, a unique method for one-step surface-plasma-induced exfoliation of a graphite/bulk transitional-metal dichalcogenide (TMD) bilayer for the preparation of graphene (Gs)/TMD nanosheet composites is presented, using Gs−tungsten disulfide (WS 2 ) nanocomposites that functioned as electrocatalysts for the hydrogen evolution reaction (HER) as our case study. This approach of producing nanocomposites is universal for all TMD materials with a graphite substrate layer that generates surface plasma when serving as the cathode under 65 V in a 1 M H 2 SO 4 or KOH electrolyte at 90 °C for 50 min. After characterizing the resultant binary nanocomposites, we found that the optimal HER performance occurred for the resultant binary nanocomposites (GW3−H 2 SO 4 ) that is produced from a graphite/bulk WS 2 bilayer (thickness ratio 0.13:0.03 mm) with 1 M H 2 SO 4 as the electrolyte; it has a low overpotential of 180 mV at a current density of 10 mA cm −2 with a low Tafel slope of 76 mV dec −1 and with high stability up to 30 h. This cost-effective and scalable one-step techniquecombining two dissimilar two-dimensional nanostructured compositesfor electrocatalytic applications appears to be an efficient means of fabricating Gs/TMD nanosheet composites suitable for use as HER electrocatalysts.

In this report, we demonstrated that the incorporation of 15 wt % two-dimensional transition-metal dichalcogenide materials indium selenide (In 2 Se 3 ) nanosheets into a polymer (PM6)/small molecule (Y6) active layer not only increased its light absorption but also enhanced the long-term stability of the PM6/Y6/In 2 Se 3 ternary blend organic photovoltaic (OPV) devices. The power conversion efficiency (PCE) of the device was improved from 15.7 to 16.5% for the corresponding PM6/Y6 binary blend device. Moreover, the PM6/Y6/In 2 Se 3 device retained 80% of its initial PCE after thermal treatment at 100 °C for 600 h; in comparison, the binary blend device retained only 62% of its initial value. This relative enhancement of 29% resulted from the In 2 Se 3 nanosheets retarding or facilitating molecule packing in different orientations that stabilizes the morphology of the active layer. We adopted a modified kinetics model to account for the intrinsic degradation of the OPV; the degradation-facilitated energy for the degradation kinetics of the PCE for the ternary blend device was 5.3 kJ/mol, half of that (11.3 kJ/mol) of the binary blend device, indicating a slower degradation rate occurring for the case of incorporating In 2 Se 3 nanosheets. Therefore, the incorporation of transition metal dichalcogenide nanosheets having tunable band gaps and large asymmetric shape appears to be a new way to improve the long-term stability of devices and realize the practical use of OPVs.

This paper analyzes the effectiveness of existing financial incentives for mangrove conservation in Vietnam. Current conservation programs and projects have created financial incentives for mangrove protection, but the effectiveness of these incentives in addressing mangrove loss in northern Vietnam has been mixed. While financial incentives have contributed to a larger area of planted mangroves, their effectiveness is hampered by contradictory national policies, which encourage mangrove conservation on the one hand, and aquaculture expansion in mangrove areas on the other, thus making it difficult to address mangrove deforestation and degradation effectively. Mangrove conservation in Vietnam is challenged further by inequitable distribution of power and benefits, difficulties accessing information, weak law enforcement, lack of compliance, low payments for protecting mangroves, lack of full recognition of local rights, discontinued funding after policies and projects end, and lack of participation by local people in policy and project design and implementation. Conservation policies and projects should aim to protect existing mangrove forests, restore degraded mangroves and plant new ones to enhance mangrove area, quality and biodiversity. Sustainable mangrove conservation not only requires effective and sustainable financial incentives, but other enabling conditions such as addressing the conflict between mangrove conservation and aquaculture expansion, and grounding mangrove conservation projects by building on local knowledge and leadership. As these drivers are often motivated by national development goals and other sectoral development needs with ministries competing for budgets and influence, holistic land-use planning needs to be coupled with effective coordination and clarification of responsibilities between government agencies, and coordinated and consistent policies concerning these natural resources. Addressing these underlying governance issues is far more important for mangrove conservation and restoration than merely offering financial incentives as various national and international projects have attempted.

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