Controller:
public function catalogAction()
	{
		$count = 10;
		if (strcasecmp($_POST['action'], 'loadContent') == 0) {
			$count = $_POST['id'];
		}
		$pagination = new Pagination($this->route, $this->model->productsCount());
		$vars = array(
			'pagination' => $pagination->get(),
			'count' => $count,
			'list' => $this->model->productsList($this->route,(int)$count),
		);
		if (strcasecmp($_POST['action'], 'loadContent') != 0) {
			$this->view->render('Каталог', $vars);
		}
	}

View:
<script>
$(document).on('click','.read-more',function(e){
	e.preventDefault();
	var id = $(this).data('id') || 0;
	// Вставляем полученный контент в HTML блок с id="content"
	$("#content").load("/catalog/",{action:"loadContent", id:id});
});
</script>
<div  class="catalog-page-title">
	<h1 class="page-title"><a href="/">Главная</a> > Каталог</h1>
</div>

<?php if (empty($list)): ?>
	<div class="empty-container">
		<p>Каталоги ненайдены</p>
	</div>
<?php else: ?>

		<div class="catalog-container">
		<?php foreach ($list as $val): ?>
			<div class="catalog-block">
				<div class="catalog-img-block">
					<a class="" href="/catalog/<?php echo $val['id']; ?>">
						<img src="public/images/1.jpg" alt="Изображение">
					</a>
				</div>
				<div class="catalog-info-title">
					<a href="/catalog/<?php echo $val['id']; ?>"><?php echo htmlspecialchars($val['title'], ENT_QUOTES); ?></a>
				</div>
			</div>
		<?php endforeach; ?>
		</div>

	<div id="getContent">
		<a class="read-more" data-id="<?php echo $vars['count']+10; ?>" href="#">Подробнее</a>
		<div id="content"></div>
	</div>
   <?php endif; ?>